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Kripke semantics

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Possible world semantics is a broader term encompassing various approaches, including Kripke semantics. It generally refers to the idea of analyzing modal statements by considering alternative possible worlds where different propositions are true or false. While Kripke semantics is a specific type of
7998:, developed a translation of sentential modal logic into classical predicate logic that, if he had combined it with the usual model theory for the latter, would have produced a model theory equivalent to Kripke models for the former. But his approach was resolutely syntactic and anti-model-theoretic. 7850:
The main defect of Kripke semantics is the existence of Kripke incomplete logics, and logics which are complete but not compact. It can be remedied by equipping Kripke frames with extra structure which restricts the set of possible valuations, using ideas from algebraic semantics. This gives rise to
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and Tarski established the representability of Boolean algebras with operators in terms of frames. If the two ideas had been put together, the result would have been precisely frame models, which is to say Kripke models, years before Kripke. But no one (not even Tarski) saw the connection at the
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possible world semantics, there are other ways to model possible worlds and their relationships. Kripke semantics is a specific form of possible world semantics that employs relational structures to represent the relationships between possible worlds and propositions in modal logic.
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gave a semantics in his papers introducing epistemic logic that is a simple variation of Kripke's semantics, equivalent to the characterisation of valuations by means of maximal consistent sets. He doesn't give inference rules for epistemic logic, and so cannot give a completeness
1142:, are valid in every Kripke model). However, the converse does not hold in general: while most of the modal systems studied are complete of classes of frames described by simple conditions, Kripke incomplete normal modal logics do exist. A natural example of such a system is 7975:
for the modalities of necessity and possibility by means of giving the valuation function a parameter that ranges over Leibnizian possible worlds. Bayart develops this idea further, but neither gave recursive definitions of satisfaction in the style introduced by
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Blackburn et al. (2001) point out that because a relational structure is simply a set together with a collection of relations on that set, it is unsurprising that relational structures are to be found just about everywhere. As an example from
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had many of the key ideas contained in Kripke's work, but he did not regard them as significant, because he had no completeness proof, and so did not publish until after Kripke's papers had created a sensation in the logic
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gave a rather more complex approach to the interpretation of modal logic, but one that contains many of the key ideas of Kripke's approach. He first noted the relationship between conditions on accessibility relations and
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The axioms T, 4, D, B, 5, H, G (and thus any combination of them) are canonical. GL and Grz are not canonical, because they are not compact. The axiom M by itself is not canonical (Goldblatt, 1991), but the combined logic
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developed an approach to modeling modal logics that is still influential in modern research, namely the algebraic approach, in which Boolean algebras with operators are used as models.
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A union of canonical sets of formulas is itself canonical. It follows from the preceding discussion that any logic axiomatized by a canonical set of formulas is Kripke complete, and
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Carlson models are easier to visualize and to work with than usual polymodal Kripke models; there are, however, Kripke complete polymodal logics which are Carlson incomplete.
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presented a semantics of intuitionistic logic based on trees, which closely resembles Kripke semantics, except for using a more cumbersome definition of satisfaction.
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There are various methods for establishing FMP for a given logic. Refinements and extensions of the canonical model construction often work, using tools such as
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modal formulae can be meaningfully 'understood'. Thus: whereas the notion of 'has a model' in classical non-modal logic refers to some individual formula
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The Search for Certainty : A Philosophical Account of Foundations of Mathematics: A Philosophical Account of Foundations of Mathematics
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The following table lists common modal axioms together with their corresponding classes. The naming of the axioms often varies; Here, axiom
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and other non-classical systems. The development of Kripke semantics was a breakthrough in the theory of non-classical logics, because the
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The key property which follows from this definition is that bisimulations (hence also p-morphisms) of models preserve the satisfaction of
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modal algebra can be transformed into a Kripke frame. As an example, Robert Bull proved using this method that every normal extension of
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The following table lists several common normal modal systems. Frame conditions for some of the systems were simplified: the logics are
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In some cases, we can use FMP to prove Kripke completeness of a logic: every normal modal logic is complete with respect to a class of
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a specific 'something' that makes a specific modal formula true; in Kripke semantics a 'model' must rather be understood as a larger
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than to prove its completeness, thus correspondence serves as a guide to completeness proofs. Correspondence is also used to show
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Kripke semantics has a straightforward generalization to logics with more than one modality. A Kripke frame for a language with
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of such logics was almost non-existent before Kripke (algebraic semantics existed, but were considered 'syntax in disguise').
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This is a powerful criterion: for example, all axioms listed above as canonical are (equivalent to) Sahlqvist formulas.
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follows the same principles as the semantics of modal logic, but it uses a different definition of satisfaction.
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but many applications need the reflexive and/or transitive closure of this relation, or similar modifications.
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from the notion of 'model' in classical non-modal logics: In classical logics we say that some formula
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The main application of canonical models are completeness proofs. Properties of the canonical model of
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As in the case of unravelling, the definition of the accessibility relation on the quotient varies.
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there is an algorithm that computes the corresponding frame condition to a given Sahlqvist formula.
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Intuitionistic logic is sound and complete with respect to its Kripke semantics, and it has the
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which has FMP is decidable, provided it is decidable whether a given finite frame is a model of
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preserves the accessibility relation, and (in both directions) satisfaction of variables
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Gasquet, Olivier; Herzig, Andreas; Said, Bilal; Schwarzentruber, François (2013).
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that logic, the notion of 'has a model' in modal logic refers to the logic itself
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Most of the modal systems used in practice (including all listed above) have FMP.
8708: 8671: 8642: 8568: 8547: 8449: 8421: 8374: 8370: 8324: 8296: 8252: 8012: 4200: 4014: 3669: 2849:{\displaystyle w\,R\,u\land w\,R\,v\Rightarrow \exists x\,(u\,R\,x\land v\,R\,x)} 2127: 1637: 353: 8651: 8088: 1569:
generates an incomplete logic, as it corresponds to the same class of frames as
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A simplified semantics, discovered by Tim Carlson, is often used for polymodal
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is Kripke complete if and only if it is complete of its corresponding class.
1106: 139: 8355:. Handbook of Philosophical Logic. Vol. 3. Springer. pp. 225–339. 7991: 7760: 6841: 6435: 6431:, there are methods for constructing a new Kripke model from other models. 6428: 6412: 6404: 4816: 4188:. In particular, every finitely axiomatizable logic with FMP is decidable. 3642: 3624: 3318: 2459: 1573:(viz. transitive and converse well-founded frames), but does not prove the 121: 8495:. Handbook of the History of Logic. Vol. 7. Elsevier. pp. 1–98. 7964:
Similar work that predated Kripke's revolutionary semantic breakthroughs:
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A bisimulation of models is additionally required to preserve forcing of
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whether a given axiom is canonical. We know a nice sufficient condition:
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are normal modal logics that correspond to the same class of frames, but
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Multiagent Systems: Algorithmic, Game-Theoretic, and Logical Foundations
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a 'model' if there exists some 'interpretation' of the variables of
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Sheaves in Geometry and Logic: A First Introduction to Topos Theory
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with respect to the class of all Kripke frames. This argument does
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with respect to the frame classes given in the table, but they may
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It is often much easier to characterize the corresponding class of
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seems to have been the first to have the idea that one can give a
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as the set of its necessity operators consists of a non-empty set
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if no contradiction can be derived from it using the theorems of
8515:"A Kripke-Joyal Semantics for Noncommutative Logic in Quantales" 8419: 8094: 3701:) can be constructed that refutes precisely the non-theorems of 8652:"4.4 Constructive Propositional Logic — Kripke Semantics" 8524:. Vol. 6. London: College Publications. pp. 209–225. 8232:
Quasi-historical Interlude: the Road from Vienna to Los Angeles
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as models. Canonical Kripke models play a role similar to the
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Kripke's Worlds: An Introduction to Modal Logics via Tableaux
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The proof theory and semantics of intuitionistic modal logic
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the class of frames corresponding to a Sahlqvist formula is
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be a set of formulas closed under taking subformulas. An
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of the canonical model satisfies the frame conditions of
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The language of propositional modal logic consists of a
8520:. In Governatori, G.; Hodkinson, I.; Venema, Y. (eds.). 8194:, p. 20, 2.2 The semantics of intuitionistic logic. 2031:{\displaystyle w\,R\,v\wedge v\,R\,u\Rightarrow w\,R\,u} 1562:{\displaystyle \Box (A\leftrightarrow \Box A)\to \Box A} 8246: 4199:. As another possibility, completeness proofs based on 2390:{\displaystyle w\,R\,u\land w\,R\,v\Rightarrow u\,R\,v} 1022:
of frames or models, if it is valid in every member of
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Semantics is useful for investigating a logic (i.e. a
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existential quantifier on the range of quantification
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corresponds to the class of reflexive Kripke frames.
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systems created in the late 1950s and early 1960s by
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The definition of the accessibility relation 4662:{\displaystyle \langle W,\leq ,\Vdash \rangle } 2171:{\displaystyle \forall w\,\exists v\,(w\,R\,v)} 8611:. In Zamuner, Edoardo; Levy, David K. (eds.). 8401:Intuitionistic Logic, Model Theory and Forcing 8351:. In Gabbay, Dov M.; Guenthner, Franz (eds.). 7604:{\displaystyle \langle W',R',\Vdash '\rangle } 7177:{\displaystyle \langle W',R',\Vdash '\rangle } 6719:{\displaystyle \langle W',R',\Vdash '\rangle } 4501:for each modality. Satisfaction is defined as 3108:{\displaystyle \forall w\,\exists !u\,w\,R\,u} 1615: 1522:is Kripke incomplete. For example, the schema 8605:"The architecture of meaning: Wittgenstein's 8271: 7500:is a useful construction which uses to prove 5567:{\displaystyle w\Vdash P(t_{1},\dots ,t_{n})} 4033:has a counterexample in the canonical model. 2329:{\displaystyle \Diamond A\to \Box \Diamond A} 1327:. On the other hand, a frame which validates 7751:preserves satisfaction of all formulas from 7598: 7565: 7537: 7519: 7477: 7413: 7400: 7355: 7246: 7201: 7171: 7138: 7107: 7089: 7071:formulas, not only propositional variables. 6909: 6887: 6867: 6855: 6713: 6680: 6660: 6642: 6564:preserves the accessibility relation, i.e., 6507: 6485: 6465: 6453: 5305: 5293: 5273: 5258: 5244: 5229: 4688: 4676: 4656: 4638: 4473: 4452: 4438: 4423: 4271: 4245: 4029:, in particular every formula unprovable in 3784: 3766: 2443:{\displaystyle \Box (\Box A\to A)\to \Box A} 1247: 1235: 982: 964: 944: 932: 875: 857: 444: 432: 412: 394: 331: 319: 289:{\displaystyle \Diamond A:=\neg \Box \neg A} 8702: 8649: 8573:. Cambridge University Press. p. 397. 8230:, See the last two paragraphs in Section 3 8204: 8129:true; this specific interpretation is then 7932:. Unsourced material may be challenged and 7543:{\displaystyle \langle W,R,\Vdash \rangle } 7113:{\displaystyle \langle W,R,\Vdash \rangle } 6726:is a p-morphism of their underlying frames 6666:{\displaystyle \langle W,R,\Vdash \rangle } 4180:that a recursively axiomatized modal logic 3790:{\displaystyle \langle W,R,\Vdash \rangle } 988:{\displaystyle \langle W,R,\Vdash \rangle } 881:{\displaystyle \langle W,R,\Vdash \rangle } 418:{\displaystyle \langle W,R,\Vdash \rangle } 127: 8567:Shoham, Yoav; Leyton-Brown, Kevin (2008). 8509: 8475: 8215: 8203:See a slightly different formalization in 7893: 7845: 7501: 7412: 7403: 6403:As part of the independent development of 5144:, could be defined as an abbreviation for 4577: 4573: 4373: 4362: 4277:{\displaystyle \{\Box _{i}\mid \,i\in I\}} 3850: 3846: 3410:is similar to the implicit implication by 2288:{\displaystyle w\,R\,v\Rightarrow v\,R\,w} 732: 728: 8486:. In Gabbay, Dov M.; Woods, John (eds.). 8447: 8343: 8276:. In Gabbay, D.M.; Guenthner, F. (eds.). 8166: 7952:Learn how and when to remove this message 6398: 6232: 6099: 4566: 4355: 4261: 3582: 3578: 3571: 3558: 3554: 3547: 3540: 3231: 3227: 3217: 3210: 3101: 3097: 3093: 3083: 3004: 3000: 2990: 2986: 2907: 2903: 2839: 2835: 2825: 2821: 2814: 2801: 2797: 2787: 2783: 2662: 2658: 2648: 2644: 2634: 2630: 2620: 2616: 2383: 2379: 2369: 2365: 2355: 2351: 2281: 2277: 2267: 2263: 2161: 2157: 2150: 2143: 2024: 2020: 2010: 2006: 1996: 1992: 1919: 1915: 1905: 1901: 1894: 1881: 1877: 1807: 1803: 1172:is the largest class of frames such that 69:Learn how and when to remove this message 8454:. Oxford University Press. p. 256. 8272:Bull, Robert A.; Segerberg, K. (2012) . 4206:usually produce finite models directly. 4196: 4192: 4161: 1053:A modal logic (i.e., a set of formulas) 32:This article includes a list of general 8615:. London: Routledge. pp. 211–244. 8602: 8587: 8393: 8369: 8295:Chagrov, A.; Zakharyaschev, M. (1997). 8227: 8191: 7074:We can transform a Kripke model into a 5311:{\displaystyle \langle W,\leq \rangle } 4694:{\displaystyle \langle W,\leq \rangle } 4082:is valid in every frame that satisfies 3417: 8724: 8703:Moschovakis, Joan (16 December 2022). 8665: 6422: 6251:{\displaystyle w\Vdash (\forall x\,A)} 6118:{\displaystyle w\Vdash (\exists x\,A)} 5466:, we define the satisfaction relation 2926:{\displaystyle w\,R\,v\Rightarrow w=v} 481:and modal formulas, such that for all 6915:{\displaystyle \langle W',R'\rangle } 6513:{\displaystyle \langle W',R'\rangle } 5640:{\displaystyle P(t_{1},\dots ,t_{n})} 4486:with a single accessibility relation 3713:construction in algebraic semantics. 1970:{\displaystyle \Box A\to \Box \Box A} 1855:{\displaystyle \Box \Box A\to \Box A} 1605:{\displaystyle \Box A\to \Box \Box A} 7930:adding citations to reliable sources 7897: 7345:varies; in the simplest case we put 5366:realizations of function symbols in 4725:satisfies the following conditions: 4227: 2964:{\displaystyle \Diamond A\to \Box A} 2241:{\displaystyle \Diamond \Box A\to A} 2209:{\displaystyle A\to \Box \Diamond A} 2069:{\displaystyle \Box A\to \Diamond A} 299: 210:("necessarily"). The modal operator 18: 8714:Stanford Encyclopedia of Philosophy 8677:Stanford Encyclopedia of Philosophy 8662:N.B: Constructive = intuitionistic. 8636: 7755:. In typical applications, we take 7188:is the set of all finite sequences 6873:{\displaystyle \langle W,R\rangle } 6471:{\displaystyle \langle W,R\rangle } 5318:is an intuitionistic Kripke frame, 4021:-consistent set is contained in an 3744:-consistent set that has no proper 3688: 1253:{\displaystyle \langle W,R\rangle } 950:{\displaystyle \langle W,R\rangle } 450:{\displaystyle \langle W,R\rangle } 337:{\displaystyle \langle W,R\rangle } 13: 8657:Introduction to Mathematical Logic 7994:, building on unpublished work of 6840:P-morphisms are a special kind of 6419:is often used in this connection. 6226: 6093: 6053: 5696:{\displaystyle w\Vdash (A\land B)} 5119: 4547: 4533:{\displaystyle w\Vdash \Box _{i}A} 4349: 4335:{\displaystyle w\Vdash \Box _{i}A} 4040:immediately imply completeness of 3997:The canonical model is a model of 3682:transitive, serial, and Euclidean 3565: 3541: 3534: 3397: 3365: 3218: 3211: 3204: 3182: 3122: 3084: 3077: 2808: 2144: 2137: 2112: 2106: 2086: 1888: 1063:with respect to a class of frames 513: 280: 274: 230:("possibly") is (classically) the 177: 38:it lacks sufficient corresponding 14: 8768: 8666:Garson, James (23 January 2023). 8630: 8613:Wittgenstein's Enduring Arguments 8379:(2nd ed.). Clarendon Press. 8326:A New Introduction to Modal Logic 7059:, for any propositional variable 6832:, for any propositional variable 5815:{\displaystyle w\Vdash (A\lor B)} 4616:Semantics of intuitionistic logic 4224:has FMP, and is Kripke complete. 4144:a Sahlqvist formula is canonical, 3864:if and only if for every formula 8596:Edinburgh Research Archive (ERA) 7902: 6383:) is the evaluation which gives 5934:{\displaystyle w\Vdash (A\to B)} 5206:Intuitionistic first-order logic 4846:{\displaystyle w\Vdash A\land B} 23: 8353:Alternatives to Classical Logic 6756:{\displaystyle f\colon W\to W'} 6550:{\displaystyle f\colon W\to W'} 6438:in Kripke semantics are called 6125:if and only if there exists an 4932:{\displaystyle w\Vdash A\lor B} 4288:equipped with binary relations 4063:We say that a formula or a set 3310:{\displaystyle \Box \to \Box B} 2118:{\displaystyle \neg \Box \bot } 1508:does not prove all theorems of 1101:Correspondence and completeness 477:is a relation between nodes of 348:is a (possibly empty) set, and 258:in terms of necessity like so: 8426:. Springer. pp. XV, 198. 8257:. Cambridge University Press. 8197: 8172: 8100: 8083:Shoham & Leyton-Brown 2008 8066: 7681:{\displaystyle u\Vdash \Box A} 6924:B ⊆ W × W’ 6808: 6802: 6742: 6635:A p-morphism of Kripke models 6536: 6354: 6351: 6345: 6339: 6333: 6245: 6239: 6236: 6223: 6195: 6192: 6186: 6180: 6174: 6112: 6106: 6103: 6090: 6062: 6056: 6024: 6018: 5989: 5983: 5928: 5922: 5919: 5913: 5907: 5879: 5873: 5844: 5838: 5809: 5803: 5800: 5788: 5760: 5754: 5725: 5719: 5690: 5684: 5681: 5669: 5634: 5631: 5625: 5603: 5597: 5584: 5561: 5555: 5552: 5520: 5488: 5482: 5018:{\displaystyle w\Vdash A\to B} 5009: 4593: 4581: 4567: 4389: 4377: 4356: 3601: 3598: 3586: 3572: 3548: 3391: 3371:{\displaystyle \Diamond \top } 3317:, which logically establishes 3298: 3295: 3286: 3280: 3274: 3271: 3235: 3221: 3049: 3008: 2952: 2911: 2872: 2843: 2815: 2805: 2749: 2698: 2638: 2592: 2586: 2577: 2568: 2562: 2553: 2511: 2508: 2502: 2499: 2490: 2484: 2478: 2431: 2428: 2422: 2413: 2373: 2314: 2271: 2232: 2194: 2165: 2151: 2092:{\displaystyle \Diamond \top } 2057: 2014: 1955: 1923: 1895: 1885: 1843: 1772: 1737: 1728: 1719: 1716: 1713: 1707: 1701: 1590: 1550: 1547: 1538: 1532: 1403:{\displaystyle w\Vdash \Box p} 1282:{\displaystyle w\Vdash \Box A} 1204: 1042:is a set of formulas, let Mod( 665:{\displaystyle w\Vdash \Box A} 582:{\displaystyle w\Vdash A\to B} 573: 522:{\displaystyle w\Vdash \neg A} 157: 1: 8278:Extensions of Classical Logic 8240: 7859:Computer science applications 7337:for a propositional variable 7330:{\displaystyle w_{n}\Vdash p} 6825:{\displaystyle f(w)\Vdash 'p} 6068:{\displaystyle w\Vdash \bot } 5356:is included in the domain of 5125:{\displaystyle w\Vdash \bot } 4733:is a propositional variable, 3697:, a Kripke model (called the 3430:to a larger class of frames. 112:. It was first conceived for 7880:theoretical computer science 6391:, and otherwise agrees with 5459:of variables by elements of 5218:language. A Kripke model of 3693:For any normal modal logic, 995:for all possible choices of 146:, a set of truth-functional 7: 8691:Encyclopedia of Mathematics 8033: 7759:as the projection onto the 7710:{\displaystyle \Box A\in X} 7052:{\displaystyle w'\Vdash 'p} 4629:intuitionistic Kripke model 4089:for any normal modal logic 4071:with respect to a property 3906:{\displaystyle \Box A\in X} 2884:{\displaystyle A\to \Box A} 1781:{\displaystyle \Box A\to A} 1616:Common modal axiom schemata 1213:{\displaystyle \Box A\to A} 1144:Japaridze's polymodal logic 10: 8773: 8650:Detlovs, V.; Podnieks, K. 8448:Giaquinto, Marcus (2002). 7884:labeled transition systems 7862: 6409:existential quantification 6310:{\displaystyle a\in M_{u}} 6151:{\displaystyle a\in M_{w}} 4231: 4176:question: it follows from 3348:{\displaystyle \Diamond A} 3188:{\displaystyle \Box \bot } 2532:reflexive and transitive, 1752:holds true for any frames 608:{\displaystyle w\nVdash A} 548:{\displaystyle w\nVdash A} 190:), and the modal operator 131: 92:, and often confused with 7831:{\displaystyle v\Vdash A} 7805:{\displaystyle u\Vdash A} 7736:{\displaystyle v\Vdash A} 7297:{\displaystyle s\Vdash p} 7016:{\displaystyle w\Vdash p} 6785:{\displaystyle w\Vdash p} 6360:{\displaystyle u\Vdash A} 6258:if and only if for every 6201:{\displaystyle w\Vdash A} 6030:{\displaystyle u\Vdash B} 5995:{\displaystyle u\Vdash A} 5885:{\displaystyle w\Vdash B} 5850:{\displaystyle w\Vdash A} 5766:{\displaystyle w\Vdash B} 5731:{\displaystyle w\Vdash A} 5494:{\displaystyle w\Vdash A} 5329:-structure for each node 5096:{\displaystyle u\Vdash B} 5070:{\displaystyle u\Vdash A} 4984:{\displaystyle w\Vdash B} 4958:{\displaystyle w\Vdash A} 4898:{\displaystyle w\Vdash B} 4872:{\displaystyle w\Vdash A} 4804:{\displaystyle u\Vdash p} 4778:{\displaystyle w\Vdash p} 4009:contains all theorems of 3960:{\displaystyle X\Vdash A} 3711:Lindenbaum–Tarski algebra 3325:in every possible world. 3140:uniqueness quantification 3131:{\displaystyle \exists !} 1487:of modal logics: suppose 1429:{\displaystyle w\Vdash p} 1362:{\displaystyle u\Vdash p} 1331:has to be reflexive: fix 1308:{\displaystyle w\Vdash A} 907:{\displaystyle w\Vdash A} 769:{\displaystyle w\Vdash A} 691:{\displaystyle u\Vdash A} 634:{\displaystyle w\Vdash B} 223:{\displaystyle \Diamond } 8603:Stokhof, Martin (2008). 8376:Elements of Intuitionism 8125:which makes the formula 8060: 7973:possible world semantics 3730:maximal L-consistent set 1452:using the definition of 128:Semantics of modal logic 94:possible world semantics 8660:. University of Latvia. 8522:Advances in Modal Logic 7894:History and terminology 7869:state transition system 7846:General frame semantics 7778:if and only if for all 7512:-filtration of a model 6277:{\displaystyle u\geq w} 5960:{\displaystyle u\geq w} 5941:if and only if for all 5044:{\displaystyle u\geq w} 5025:if and only if for all 4752:{\displaystyle w\leq u} 4718:{\displaystyle \Vdash } 3857:{\displaystyle X\;R\;Y} 3826:{\displaystyle \Vdash } 3707:maximal consistent sets 1814:{\displaystyle w\,R\,w} 1465:{\displaystyle \Vdash } 1008:{\displaystyle \Vdash } 813:{\displaystyle \Vdash } 739:{\displaystyle w\;R\;u} 470:{\displaystyle \Vdash } 457:is a Kripke frame, and 144:propositional variables 116:, and later adapted to 53:more precise citations. 8705:"Intuitionistic Logic" 8588:Simpson, Alex (1994). 8371:Dummett, Michael A. E. 8349:"Intuitionistic Logic" 8251:; Venema, Yde (2002). 7832: 7806: 7737: 7711: 7682: 7605: 7544: 7484: 7331: 7298: 7253: 7178: 7114: 7053: 7017: 6916: 6874: 6826: 6786: 6757: 6720: 6667: 6551: 6514: 6472: 6417:Kripke–Joyal semantics 6399:Kripke–Joyal semantics 6361: 6311: 6278: 6252: 6202: 6152: 6119: 6069: 6031: 5996: 5961: 5935: 5886: 5851: 5816: 5767: 5732: 5697: 5641: 5568: 5495: 5312: 5280: 5126: 5097: 5071: 5045: 5019: 4985: 4959: 4933: 4899: 4873: 4847: 4805: 4779: 4753: 4719: 4695: 4663: 4603: 4534: 4480: 4399: 4336: 4278: 3987: 3986:{\displaystyle A\in X} 3961: 3933: 3932:{\displaystyle A\in Y} 3907: 3878: 3858: 3827: 3791: 3748:-consistent superset. 3728:, and Modus Ponens. A 3608: 3404: 3372: 3349: 3311: 3242: 3189: 3166: 3165:{\displaystyle \Box A} 3132: 3109: 3062: 3024: 2965: 2927: 2885: 2850: 2765: 2714: 2670: 2599: 2521: 2444: 2391: 2330: 2289: 2242: 2210: 2172: 2119: 2093: 2070: 2032: 1971: 1930: 1856: 1815: 1782: 1744: 1670:symbolic logic systems 1606: 1563: 1466: 1430: 1404: 1363: 1309: 1283: 1254: 1214: 1130:of Kripke frames, Thm( 1009: 989: 951: 908: 882: 814: 770: 740: 712: 692: 666: 635: 609: 583: 549: 523: 471: 451: 419: 378:accessibility relation 338: 290: 248: 224: 204: 184: 164: 140:countably infinite set 8609:and formal semantics" 8143:universe of discourse 8055:Muddy Children Puzzle 7833: 7807: 7738: 7712: 7683: 7606: 7545: 7504:for many logics. Let 7485: 7332: 7299: 7254: 7179: 7115: 7054: 7018: 6917: 6875: 6827: 6787: 6758: 6721: 6668: 6552: 6515: 6473: 6362: 6312: 6279: 6253: 6203: 6153: 6120: 6070: 6032: 5997: 5962: 5936: 5887: 5852: 5817: 5768: 5733: 5698: 5642: 5569: 5496: 5380:agree on elements of 5313: 5281: 5200:finite model property 5127: 5098: 5072: 5046: 5020: 4986: 4960: 4934: 4900: 4874: 4848: 4806: 4780: 4754: 4720: 4696: 4664: 4620:Kripke semantics for 4604: 4535: 4481: 4400: 4337: 4279: 4169:finite model property 4162:Finite model property 4075:of Kripke frames, if 3988: 3962: 3934: 3908: 3879: 3859: 3828: 3792: 3716:A set of formulas is 3609: 3405: 3373: 3350: 3312: 3243: 3190: 3167: 3133: 3110: 3063: 3025: 2966: 2928: 2886: 2851: 2766: 2715: 2671: 2600: 2522: 2445: 2392: 2331: 2290: 2243: 2211: 2173: 2120: 2094: 2071: 2033: 1972: 1931: 1857: 1816: 1783: 1745: 1607: 1564: 1467: 1431: 1405: 1364: 1310: 1284: 1255: 1215: 1156:to a class of frames 1149:A normal modal logic 1116:syntactic consequence 1010: 990: 952: 909: 883: 822:satisfaction relation 815: 771: 741: 713: 693: 667: 636: 610: 584: 550: 524: 472: 452: 420: 339: 291: 249: 247:{\displaystyle \Box } 225: 205: 203:{\displaystyle \Box } 185: 183:{\displaystyle \neg } 165: 7979:J.C.C. McKinsey and 7926:improve this section 7816: 7790: 7721: 7692: 7663: 7562: 7516: 7352: 7308: 7282: 7192: 7135: 7131:, we define a model 7086: 7027: 7001: 6884: 6852: 6796: 6770: 6730: 6677: 6639: 6524: 6482: 6450: 6442:(which is short for 6321: 6288: 6262: 6214: 6162: 6129: 6081: 6044: 6006: 5971: 5945: 5898: 5861: 5826: 5779: 5742: 5707: 5660: 5578: 5508: 5470: 5455:Given an evaluation 5290: 5226: 5110: 5081: 5055: 5029: 4997: 4969: 4943: 4911: 4883: 4857: 4825: 4789: 4763: 4737: 4709: 4673: 4635: 4622:intuitionistic logic 4544: 4508: 4420: 4346: 4310: 4242: 3971: 3945: 3917: 3888: 3868: 3840: 3817: 3809:, and the relations 3763: 3643:strict partial order 3531: 3502:equivalence relation 3446: 3418:Common modal systems 3382: 3359: 3336: 3328:Note that for axiom 3265: 3201: 3176: 3153: 3119: 3074: 3040: 2980: 2943: 2897: 2866: 2777: 2737: 2686: 2610: 2547: 2472: 2407: 2345: 2305: 2257: 2220: 2188: 2134: 2103: 2080: 2048: 1986: 1946: 1871: 1831: 1797: 1763: 1695: 1581: 1526: 1456: 1414: 1385: 1347: 1293: 1264: 1232: 1195: 1187:Consider the schema 1111:semantic consequence 999: 961: 957:, if it is valid in 929: 892: 854: 804: 754: 722: 702: 676: 647: 619: 593: 561: 533: 504: 461: 429: 391: 316: 262: 238: 214: 194: 174: 163:{\displaystyle \to } 154: 118:intuitionistic logic 86:relational semantics 8757:Non-classical logic 8747:Philosophical logic 8301:. Clarendon Press. 8274:"Basic Modal Logic" 8180:Andrzej Grzegorczyk 8095:Gasquet et al. 2013 8040:Alexandrov topology 6423:Model constructions 5444:, then it holds in 4048:work for arbitrary 3355:implicitly implies 1664:are named based on 1632:is named after the 1168:). In other words, 489:and modal formulas 102:non-classical logic 8742:Mathematical logic 8540:Mac Lane, Saunders 8205:Moschovakis (2022) 8050:Two-dimensionalism 8045:Normal modal logic 7828: 7802: 7767:over the relation 7733: 7707: 7678: 7601: 7540: 7480: 7327: 7294: 7249: 7174: 7110: 7049: 7013: 6963:u’ R’ v’ 6952:u’ R’ v’ 6912: 6870: 6822: 6782: 6763:, which satisfies 6753: 6716: 6663: 6547: 6510: 6468: 6444:pseudo-epimorphism 6357: 6307: 6274: 6248: 6198: 6148: 6115: 6065: 6027: 5992: 5957: 5931: 5882: 5847: 5812: 5763: 5728: 5693: 5637: 5564: 5491: 5308: 5276: 5122: 5093: 5067: 5041: 5015: 4981: 4955: 4929: 4895: 4869: 4843: 4801: 4775: 4749: 4715: 4705:Kripke frame, and 4691: 4659: 4599: 4530: 4476: 4410:provability logics 4395: 4332: 4274: 4138:Sahlqvist formulas 4128:In general, it is 3983: 3957: 3929: 3903: 3874: 3854: 3823: 3801:is the set of all 3787: 3759:is a Kripke model 3604: 3424:sound and complete 3400: 3368: 3345: 3307: 3238: 3185: 3162: 3128: 3105: 3058: 3020: 2961: 2923: 2881: 2846: 2761: 2710: 2666: 2595: 2517: 2440: 2387: 2326: 2285: 2238: 2206: 2168: 2115: 2089: 2066: 2028: 1967: 1926: 1852: 1811: 1778: 1740: 1602: 1559: 1462: 1426: 1400: 1359: 1305: 1279: 1250: 1210: 1180:. It follows that 1136:normal modal logic 1038:. Conversely, if 1005: 985: 947: 904: 878: 810: 766: 736: 708: 688: 662: 631: 605: 579: 545: 519: 467: 447: 415: 334: 286: 244: 220: 200: 180: 160: 8637:Burgess, John P. 8559:978-1-4612-0927-0 8511:Goldblatt, Robert 8502:978-0-08-046303-2 8477:Goldblatt, Robert 8412:978-0-444-53418-7 8405:. North-Holland. 8386:978-0-19-850524-2 8362:978-94-009-5203-4 8336:978-1-134-80028-5 8308:978-0-19-853779-3 8287:978-94-009-6259-0 8264:978-1-316-10195-7 8097:, pp. 14–16. 8027:Evert Willem Beth 7962: 7961: 7954: 7888:program execution 7120:and a fixed node 5325:is a (classical) 5148:→ ⊥. If for all 4228:Multimodal logics 3877:{\displaystyle A} 3740:for short) is an 3686: 3685: 3652:Grz or T, 4, Grz 3323:rule of inference 3251: 3250: 2536:−Id well-founded 1164: = Mod( 1107:derivation system 1093: ⊇ Thm( 1071: ⊆ Thm( 711:{\displaystyle u} 300:Basic definitions 150:(in this article 79: 78: 71: 8764: 8718: 8709:Zalta, Edward N. 8699: 8681: 8672:Zalta, Edward N. 8661: 8646: 8641:. Archived from 8626: 8599: 8584: 8563: 8535: 8519: 8506: 8494: 8485: 8472: 8470: 8468: 8444: 8442: 8440: 8416: 8404: 8390: 8366: 8340: 8312: 8291: 8268: 8235: 8225: 8219: 8213: 8207: 8201: 8195: 8189: 8183: 8176: 8170: 8164: 8158: 8104: 8098: 8092: 8086: 8080: 8074: 8070: 8020:Richard Montague 7957: 7950: 7946: 7943: 7937: 7906: 7898: 7865:Kripke structure 7837: 7835: 7834: 7829: 7811: 7809: 7808: 7803: 7747:It follows that 7742: 7740: 7739: 7734: 7716: 7714: 7713: 7708: 7687: 7685: 7684: 7679: 7610: 7608: 7607: 7602: 7597: 7586: 7575: 7549: 7547: 7546: 7541: 7489: 7487: 7486: 7481: 7476: 7475: 7457: 7456: 7438: 7437: 7425: 7424: 7411: 7399: 7398: 7380: 7379: 7367: 7366: 7336: 7334: 7333: 7328: 7320: 7319: 7303: 7301: 7300: 7295: 7274: <  7258: 7256: 7255: 7250: 7245: 7244: 7226: 7225: 7213: 7212: 7183: 7181: 7180: 7175: 7170: 7159: 7148: 7119: 7117: 7116: 7111: 7082:. Given a model 7058: 7056: 7055: 7050: 7045: 7037: 7022: 7020: 7019: 7014: 6995:w B w’ 6975:v B v’ 6959:u B u’ 6948:v B v’ 6932:u B u’ 6921: 6919: 6918: 6913: 6908: 6897: 6879: 6877: 6876: 6871: 6844:. In general, a 6831: 6829: 6828: 6823: 6818: 6791: 6789: 6788: 6783: 6762: 6760: 6759: 6754: 6752: 6725: 6723: 6722: 6717: 6712: 6701: 6690: 6672: 6670: 6669: 6664: 6556: 6554: 6553: 6548: 6546: 6519: 6517: 6516: 6511: 6506: 6495: 6477: 6475: 6474: 6469: 6427:As in classical 6366: 6364: 6363: 6358: 6316: 6314: 6313: 6308: 6306: 6305: 6283: 6281: 6280: 6275: 6257: 6255: 6254: 6249: 6207: 6205: 6204: 6199: 6157: 6155: 6154: 6149: 6147: 6146: 6124: 6122: 6121: 6116: 6074: 6072: 6071: 6066: 6036: 6034: 6033: 6028: 6001: 5999: 5998: 5993: 5966: 5964: 5963: 5958: 5940: 5938: 5937: 5932: 5891: 5889: 5888: 5883: 5856: 5854: 5853: 5848: 5821: 5819: 5818: 5813: 5772: 5770: 5769: 5764: 5737: 5735: 5734: 5729: 5702: 5700: 5699: 5694: 5646: 5644: 5643: 5638: 5624: 5623: 5596: 5595: 5573: 5571: 5570: 5565: 5551: 5550: 5532: 5531: 5500: 5498: 5497: 5492: 5317: 5315: 5314: 5309: 5285: 5283: 5282: 5277: 5272: 5271: 5256: 5255: 5136:The negation of 5131: 5129: 5128: 5123: 5102: 5100: 5099: 5094: 5076: 5074: 5073: 5068: 5050: 5048: 5047: 5042: 5024: 5022: 5021: 5016: 4990: 4988: 4987: 4982: 4964: 4962: 4961: 4956: 4938: 4936: 4935: 4930: 4904: 4902: 4901: 4896: 4878: 4876: 4875: 4870: 4852: 4850: 4849: 4844: 4810: 4808: 4807: 4802: 4784: 4782: 4781: 4776: 4758: 4756: 4755: 4750: 4724: 4722: 4721: 4716: 4700: 4698: 4697: 4692: 4668: 4666: 4665: 4660: 4608: 4606: 4605: 4600: 4565: 4564: 4539: 4537: 4536: 4531: 4526: 4525: 4485: 4483: 4482: 4477: 4466: 4465: 4450: 4449: 4404: 4402: 4401: 4396: 4372: 4371: 4341: 4339: 4338: 4333: 4328: 4327: 4283: 4281: 4280: 4275: 4257: 4256: 4234:Multimodal logic 4166:A logic has the 4134:Henrik Sahlqvist 4125:) is canonical. 3992: 3990: 3989: 3984: 3966: 3964: 3963: 3958: 3938: 3936: 3935: 3930: 3912: 3910: 3909: 3904: 3883: 3881: 3880: 3875: 3863: 3861: 3860: 3855: 3833:are as follows: 3832: 3830: 3829: 3824: 3796: 3794: 3793: 3788: 3689:Canonical models 3613: 3611: 3610: 3605: 3498:T, 5 or D, B, 4 3442:Frame condition 3433: 3432: 3409: 3407: 3406: 3401: 3377: 3375: 3374: 3369: 3354: 3352: 3351: 3346: 3316: 3314: 3313: 3308: 3247: 3245: 3244: 3239: 3194: 3192: 3191: 3186: 3171: 3169: 3168: 3163: 3137: 3135: 3134: 3129: 3114: 3112: 3111: 3106: 3067: 3065: 3064: 3059: 3029: 3027: 3026: 3021: 2974:partial function 2970: 2968: 2967: 2962: 2932: 2930: 2929: 2924: 2890: 2888: 2887: 2882: 2855: 2853: 2852: 2847: 2770: 2768: 2767: 2762: 2719: 2717: 2716: 2711: 2675: 2673: 2672: 2667: 2604: 2602: 2601: 2596: 2526: 2524: 2523: 2518: 2449: 2447: 2446: 2441: 2396: 2394: 2393: 2388: 2335: 2333: 2332: 2327: 2294: 2292: 2291: 2286: 2247: 2245: 2244: 2239: 2215: 2213: 2212: 2207: 2177: 2175: 2174: 2169: 2124: 2122: 2121: 2116: 2098: 2096: 2095: 2090: 2075: 2073: 2072: 2067: 2037: 2035: 2034: 2029: 1976: 1974: 1973: 1968: 1935: 1933: 1932: 1927: 1861: 1859: 1858: 1853: 1820: 1818: 1817: 1812: 1787: 1785: 1784: 1779: 1749: 1747: 1746: 1741: 1684:Frame condition 1675: 1674: 1668:'s numbering of 1654:L. E. J. Brouwer 1611: 1609: 1608: 1603: 1568: 1566: 1565: 1560: 1471: 1469: 1468: 1463: 1435: 1433: 1432: 1427: 1409: 1407: 1406: 1401: 1368: 1366: 1365: 1360: 1314: 1312: 1311: 1306: 1288: 1286: 1285: 1280: 1259: 1257: 1256: 1251: 1224:is valid in any 1219: 1217: 1216: 1211: 1014: 1012: 1011: 1006: 994: 992: 991: 986: 956: 954: 953: 948: 913: 911: 910: 905: 887: 885: 884: 879: 819: 817: 816: 811: 800:”. The relation 788:is satisfied in 775: 773: 772: 767: 745: 743: 742: 737: 717: 715: 714: 709: 697: 695: 694: 689: 671: 669: 668: 663: 640: 638: 637: 632: 614: 612: 611: 606: 588: 586: 585: 580: 554: 552: 551: 546: 528: 526: 525: 520: 476: 474: 473: 468: 456: 454: 453: 448: 424: 422: 421: 416: 376:is known as the 343: 341: 340: 335: 295: 293: 292: 287: 253: 251: 250: 245: 229: 227: 226: 221: 209: 207: 206: 201: 189: 187: 186: 181: 169: 167: 166: 161: 82:Kripke semantics 74: 67: 63: 60: 54: 49:this article by 40:inline citations 27: 26: 19: 8772: 8771: 8767: 8766: 8765: 8763: 8762: 8761: 8722: 8721: 8686:"Kripke models" 8684: 8639:"Kripke Models" 8633: 8623: 8581: 8560: 8532: 8517: 8503: 8492: 8483: 8466: 8464: 8462: 8438: 8436: 8434: 8413: 8395:Fitting, Melvin 8387: 8363: 8345:Van Dalen, Dirk 8337: 8317:Cresswell, M.J. 8309: 8288: 8265: 8247:Blackburn, P.; 8243: 8238: 8226: 8222: 8216:Goldblatt 2006b 8214: 8210: 8202: 8198: 8190: 8186: 8177: 8173: 8165: 8161: 8105: 8101: 8093: 8089: 8081: 8077: 8071: 8067: 8063: 8036: 8013:Jaakko Hintikka 7958: 7947: 7941: 7938: 7923: 7907: 7896: 7875: 7863:Main articles: 7861: 7848: 7817: 7814: 7813: 7812:if and only if 7791: 7788: 7787: 7775: 7722: 7719: 7718: 7693: 7690: 7689: 7664: 7661: 7660: 7590: 7579: 7568: 7563: 7560: 7559: 7517: 7514: 7513: 7465: 7461: 7452: 7448: 7433: 7429: 7420: 7416: 7404: 7394: 7390: 7375: 7371: 7362: 7358: 7353: 7350: 7349: 7315: 7311: 7309: 7306: 7305: 7304:if and only if 7283: 7280: 7279: 7268: 7264: 7240: 7236: 7221: 7217: 7208: 7204: 7193: 7190: 7189: 7163: 7152: 7141: 7136: 7133: 7132: 7126: 7087: 7084: 7083: 7038: 7030: 7028: 7025: 7024: 7023:if and only if 7002: 6999: 6998: 6987:atomic formulas 6979:u R v 6965:, there exists 6938:, there exists 6936:u R v 6901: 6890: 6885: 6882: 6881: 6853: 6850: 6849: 6848:between frames 6811: 6797: 6794: 6793: 6792:if and only if 6771: 6768: 6767: 6745: 6731: 6728: 6727: 6705: 6694: 6683: 6678: 6675: 6674: 6640: 6637: 6636: 6617:u R v 6566:u R v 6539: 6525: 6522: 6521: 6499: 6488: 6483: 6480: 6479: 6451: 6448: 6447: 6425: 6401: 6322: 6319: 6318: 6301: 6297: 6289: 6286: 6285: 6263: 6260: 6259: 6215: 6212: 6211: 6163: 6160: 6159: 6142: 6138: 6130: 6127: 6126: 6082: 6079: 6078: 6045: 6042: 6041: 6007: 6004: 6003: 5972: 5969: 5968: 5946: 5943: 5942: 5899: 5896: 5895: 5862: 5859: 5858: 5827: 5824: 5823: 5822:if and only if 5780: 5777: 5776: 5743: 5740: 5739: 5708: 5705: 5704: 5703:if and only if 5661: 5658: 5657: 5652: 5619: 5615: 5591: 5587: 5579: 5576: 5575: 5574:if and only if 5546: 5542: 5527: 5523: 5509: 5506: 5505: 5471: 5468: 5467: 5464: 5449: 5442: 5435: 5429: 5417: 5410: 5404: 5394:-ary predicate 5385: 5378: 5371: 5361: 5354: 5323: 5291: 5288: 5287: 5261: 5257: 5251: 5247: 5227: 5224: 5223: 5208: 5190: 5176: 5166: 5111: 5108: 5107: 5082: 5079: 5078: 5056: 5053: 5052: 5030: 5027: 5026: 4998: 4995: 4994: 4970: 4967: 4966: 4944: 4941: 4940: 4939:if and only if 4912: 4909: 4908: 4884: 4881: 4880: 4858: 4855: 4854: 4853:if and only if 4826: 4823: 4822: 4815:condition (cf. 4790: 4787: 4786: 4764: 4761: 4760: 4738: 4735: 4734: 4710: 4707: 4706: 4674: 4671: 4670: 4636: 4633: 4632: 4618: 4560: 4556: 4545: 4542: 4541: 4540:if and only if 4521: 4517: 4509: 4506: 4505: 4495: 4455: 4451: 4445: 4441: 4421: 4418: 4417: 4416:is a structure 4367: 4363: 4347: 4344: 4343: 4342:if and only if 4323: 4319: 4311: 4308: 4307: 4293: 4252: 4248: 4243: 4240: 4239: 4236: 4230: 4204:sequent calculi 4164: 4121:(in fact, even 4067:of formulas is 3972: 3969: 3968: 3967:if and only if 3946: 3943: 3942: 3918: 3915: 3914: 3889: 3886: 3885: 3869: 3866: 3865: 3841: 3838: 3837: 3818: 3815: 3814: 3764: 3761: 3760: 3753:canonical model 3699:canonical model 3691: 3532: 3529: 3528: 3420: 3383: 3380: 3379: 3360: 3357: 3356: 3337: 3334: 3333: 3266: 3263: 3262: 3202: 3199: 3198: 3177: 3174: 3173: 3154: 3151: 3150: 3120: 3117: 3116: 3075: 3072: 3071: 3041: 3038: 3037: 2981: 2978: 2977: 2944: 2941: 2940: 2898: 2895: 2894: 2867: 2864: 2863: 2778: 2775: 2774: 2738: 2735: 2734: 2722:(a complicated 2687: 2684: 2683: 2611: 2608: 2607: 2548: 2545: 2544: 2473: 2470: 2469: 2408: 2405: 2404: 2346: 2343: 2342: 2306: 2303: 2302: 2258: 2255: 2254: 2221: 2218: 2217: 2189: 2186: 2185: 2135: 2132: 2131: 2104: 2101: 2100: 2081: 2078: 2077: 2049: 2046: 2045: 1987: 1984: 1983: 1947: 1944: 1943: 1872: 1869: 1868: 1832: 1829: 1828: 1798: 1795: 1794: 1764: 1761: 1760: 1696: 1693: 1692: 1652:is named after 1644:is named after 1638:epistemic logic 1624:is named after 1618: 1582: 1579: 1578: 1527: 1524: 1523: 1521: 1514: 1507: 1500: 1493: 1457: 1454: 1453: 1415: 1412: 1411: 1386: 1383: 1382: 1369:if and only if 1348: 1345: 1344: 1294: 1291: 1290: 1265: 1262: 1261: 1233: 1230: 1229: 1196: 1193: 1192: 1103: 1000: 997: 996: 962: 959: 958: 930: 927: 926: 893: 890: 889: 855: 852: 851: 805: 802: 801: 755: 752: 751: 723: 720: 719: 703: 700: 699: 677: 674: 673: 672:if and only if 648: 645: 644: 620: 617: 616: 594: 591: 590: 589:if and only if 562: 559: 558: 534: 531: 530: 529:if and only if 505: 502: 501: 462: 459: 458: 430: 427: 426: 392: 389: 388: 354:binary relation 317: 314: 313: 302: 263: 260: 259: 239: 236: 235: 215: 212: 211: 195: 192: 191: 175: 172: 171: 155: 152: 151: 136: 130: 90:frame semantics 84:(also known as 75: 64: 58: 55: 45:Please help to 44: 28: 24: 17: 12: 11: 5: 8770: 8760: 8759: 8754: 8749: 8744: 8739: 8734: 8720: 8719: 8700: 8682: 8663: 8647: 8645:on 2004-10-20. 8632: 8631:External links 8629: 8628: 8627: 8621: 8600: 8585: 8580:978-0521899437 8579: 8564: 8558: 8544:Moerdijk, Ieke 8536: 8530: 8507: 8501: 8473: 8460: 8445: 8433:978-3764385033 8432: 8417: 8411: 8391: 8385: 8367: 8361: 8341: 8335: 8313: 8307: 8292: 8286: 8269: 8263: 8242: 8239: 8237: 8236: 8220: 8208: 8196: 8184: 8171: 8167:Giaquinto 2002 8159: 8106:Note that the 8099: 8087: 8075: 8064: 8062: 8059: 8058: 8057: 8052: 8047: 8042: 8035: 8032: 8031: 8030: 8024: 8017: 8010: 7999: 7996:C. A. Meredith 7989: 7985:Bjarni Jónsson 7977: 7960: 7959: 7910: 7908: 7901: 7895: 7892: 7886:, which model 7873:model checking 7860: 7857: 7847: 7844: 7840: 7839: 7827: 7824: 7821: 7801: 7798: 7795: 7773: 7745: 7744: 7732: 7729: 7726: 7706: 7703: 7700: 7697: 7677: 7674: 7671: 7668: 7637: 7623: 7600: 7596: 7593: 7589: 7585: 7582: 7578: 7574: 7571: 7567: 7539: 7536: 7533: 7530: 7527: 7524: 7521: 7492: 7491: 7479: 7474: 7471: 7468: 7464: 7460: 7455: 7451: 7447: 7444: 7441: 7436: 7432: 7428: 7423: 7419: 7415: 7410: 7407: 7402: 7397: 7393: 7389: 7386: 7383: 7378: 7374: 7370: 7365: 7361: 7357: 7326: 7323: 7318: 7314: 7293: 7290: 7287: 7266: 7265: R w 7262: 7248: 7243: 7239: 7235: 7232: 7229: 7224: 7220: 7216: 7211: 7207: 7203: 7200: 7197: 7173: 7169: 7166: 7162: 7158: 7155: 7151: 7147: 7144: 7140: 7124: 7109: 7106: 7103: 7100: 7097: 7094: 7091: 7065: 7064: 7048: 7044: 7041: 7036: 7033: 7012: 7009: 7006: 6983: 6982: 6955: 6922:is a relation 6911: 6907: 6904: 6900: 6896: 6893: 6889: 6869: 6866: 6863: 6860: 6857: 6838: 6837: 6821: 6817: 6814: 6810: 6807: 6804: 6801: 6781: 6778: 6775: 6751: 6748: 6744: 6741: 6738: 6735: 6715: 6711: 6708: 6704: 6700: 6697: 6693: 6689: 6686: 6682: 6662: 6659: 6656: 6653: 6650: 6647: 6644: 6633: 6632: 6627:) =  6607:’, there is a 6589: 6545: 6542: 6538: 6535: 6532: 6529: 6509: 6505: 6502: 6498: 6494: 6491: 6487: 6467: 6464: 6461: 6458: 6455: 6424: 6421: 6400: 6397: 6369: 6368: 6356: 6353: 6350: 6347: 6344: 6341: 6338: 6335: 6332: 6329: 6326: 6304: 6300: 6296: 6293: 6273: 6270: 6267: 6247: 6244: 6241: 6238: 6235: 6231: 6228: 6225: 6222: 6219: 6209: 6197: 6194: 6191: 6188: 6185: 6182: 6179: 6176: 6173: 6170: 6167: 6145: 6141: 6137: 6134: 6114: 6111: 6108: 6105: 6102: 6098: 6095: 6092: 6089: 6086: 6076: 6064: 6061: 6058: 6055: 6052: 6049: 6038: 6026: 6023: 6020: 6017: 6014: 6011: 5991: 5988: 5985: 5982: 5979: 5976: 5956: 5953: 5950: 5930: 5927: 5924: 5921: 5918: 5915: 5912: 5909: 5906: 5903: 5893: 5881: 5878: 5875: 5872: 5869: 5866: 5846: 5843: 5840: 5837: 5834: 5831: 5811: 5808: 5805: 5802: 5799: 5796: 5793: 5790: 5787: 5784: 5774: 5762: 5759: 5756: 5753: 5750: 5747: 5727: 5724: 5721: 5718: 5715: 5712: 5692: 5689: 5686: 5683: 5680: 5677: 5674: 5671: 5668: 5665: 5655: 5650: 5636: 5633: 5630: 5627: 5622: 5618: 5614: 5611: 5608: 5605: 5602: 5599: 5594: 5590: 5586: 5583: 5563: 5560: 5557: 5554: 5549: 5545: 5541: 5538: 5535: 5530: 5526: 5522: 5519: 5516: 5513: 5490: 5487: 5484: 5481: 5478: 5475: 5462: 5453: 5452: 5447: 5440: 5433: 5427: 5415: 5408: 5402: 5388: 5383: 5376: 5369: 5364: 5359: 5352: 5349:the domain of 5321: 5307: 5304: 5301: 5298: 5295: 5275: 5270: 5267: 5264: 5260: 5254: 5250: 5246: 5243: 5240: 5237: 5234: 5231: 5207: 5204: 5188: 5182:vacuously true 5174: 5164: 5134: 5133: 5121: 5118: 5115: 5104: 5092: 5089: 5086: 5066: 5063: 5060: 5040: 5037: 5034: 5014: 5011: 5008: 5005: 5002: 4992: 4980: 4977: 4974: 4954: 4951: 4948: 4928: 4925: 4922: 4919: 4916: 4906: 4894: 4891: 4888: 4868: 4865: 4862: 4842: 4839: 4836: 4833: 4830: 4820: 4800: 4797: 4794: 4774: 4771: 4768: 4748: 4745: 4742: 4714: 4690: 4687: 4684: 4681: 4678: 4658: 4655: 4652: 4649: 4646: 4643: 4640: 4617: 4614: 4610: 4609: 4598: 4595: 4592: 4589: 4586: 4583: 4580: 4576: 4572: 4569: 4563: 4559: 4555: 4552: 4549: 4529: 4524: 4520: 4516: 4513: 4493: 4490:, and subsets 4475: 4472: 4469: 4464: 4461: 4458: 4454: 4448: 4444: 4440: 4437: 4434: 4431: 4428: 4425: 4406: 4405: 4394: 4391: 4388: 4385: 4382: 4379: 4376: 4370: 4366: 4361: 4358: 4354: 4351: 4331: 4326: 4322: 4318: 4315: 4291: 4273: 4270: 4267: 4264: 4260: 4255: 4251: 4247: 4229: 4226: 4214:modal algebras 4178:Post's theorem 4163: 4160: 4156: 4155: 4152: 4145: 4107: 4106: 4093:that contains 4087: 3995: 3994: 3982: 3979: 3976: 3956: 3953: 3950: 3940: 3928: 3925: 3922: 3902: 3899: 3896: 3893: 3873: 3853: 3849: 3845: 3822: 3786: 3783: 3780: 3777: 3774: 3771: 3768: 3690: 3687: 3684: 3683: 3680: 3677: 3673: 3672: 3667: 3664: 3660: 3659: 3653: 3650: 3646: 3645: 3639: 3636: 3629: 3628: 3622: 3619: 3615: 3614: 3603: 3600: 3597: 3594: 3591: 3588: 3585: 3581: 3577: 3574: 3570: 3567: 3564: 3561: 3557: 3553: 3550: 3546: 3543: 3539: 3536: 3525: 3522: 3518: 3517: 3515:total preorder 3512: 3509: 3505: 3504: 3499: 3496: 3490: 3489: 3484: 3481: 3477: 3476: 3473: 3470: 3466: 3465: 3462: 3459: 3455: 3454: 3451: 3448: 3444: 3443: 3440: 3437: 3419: 3416: 3399: 3396: 3393: 3390: 3387: 3367: 3364: 3344: 3341: 3306: 3303: 3300: 3297: 3294: 3291: 3288: 3285: 3282: 3279: 3276: 3273: 3270: 3249: 3248: 3237: 3234: 3230: 3226: 3223: 3220: 3216: 3213: 3209: 3206: 3195: 3184: 3181: 3161: 3158: 3148: 3144: 3143: 3127: 3124: 3104: 3100: 3096: 3092: 3089: 3086: 3082: 3079: 3068: 3057: 3054: 3051: 3048: 3045: 3035: 3031: 3030: 3019: 3016: 3013: 3010: 3007: 3003: 2999: 2996: 2993: 2989: 2985: 2971: 2960: 2957: 2954: 2951: 2948: 2938: 2934: 2933: 2922: 2919: 2916: 2913: 2910: 2906: 2902: 2891: 2880: 2877: 2874: 2871: 2861: 2857: 2856: 2845: 2842: 2838: 2834: 2831: 2828: 2824: 2820: 2817: 2813: 2810: 2807: 2804: 2800: 2796: 2793: 2790: 2786: 2782: 2771: 2760: 2757: 2754: 2751: 2748: 2745: 2742: 2732: 2728: 2727: 2720: 2709: 2706: 2703: 2700: 2697: 2694: 2691: 2681: 2677: 2676: 2665: 2661: 2657: 2654: 2651: 2647: 2643: 2640: 2637: 2633: 2629: 2626: 2623: 2619: 2615: 2605: 2594: 2591: 2588: 2585: 2582: 2579: 2576: 2573: 2570: 2567: 2564: 2561: 2558: 2555: 2552: 2542: 2538: 2537: 2527: 2516: 2513: 2510: 2507: 2504: 2501: 2498: 2495: 2492: 2489: 2486: 2483: 2480: 2477: 2467: 2463: 2462: 2450: 2439: 2436: 2433: 2430: 2427: 2424: 2421: 2418: 2415: 2412: 2402: 2398: 2397: 2386: 2382: 2378: 2375: 2372: 2368: 2364: 2361: 2358: 2354: 2350: 2336: 2325: 2322: 2319: 2316: 2313: 2310: 2300: 2296: 2295: 2284: 2280: 2276: 2273: 2270: 2266: 2262: 2248: 2237: 2234: 2231: 2228: 2225: 2205: 2202: 2199: 2196: 2193: 2183: 2179: 2178: 2167: 2164: 2160: 2156: 2153: 2149: 2146: 2142: 2139: 2125: 2114: 2111: 2108: 2088: 2085: 2065: 2062: 2059: 2056: 2053: 2043: 2039: 2038: 2027: 2023: 2019: 2016: 2013: 2009: 2005: 2002: 1999: 1995: 1991: 1977: 1966: 1963: 1960: 1957: 1954: 1951: 1941: 1937: 1936: 1925: 1922: 1918: 1914: 1911: 1908: 1904: 1900: 1897: 1893: 1890: 1887: 1884: 1880: 1876: 1862: 1851: 1848: 1845: 1842: 1839: 1836: 1826: 1822: 1821: 1810: 1806: 1802: 1788: 1777: 1774: 1771: 1768: 1758: 1754: 1753: 1750: 1739: 1736: 1733: 1730: 1727: 1724: 1721: 1718: 1715: 1712: 1709: 1706: 1703: 1700: 1690: 1686: 1685: 1682: 1679: 1617: 1614: 1601: 1598: 1595: 1592: 1589: 1586: 1558: 1555: 1552: 1549: 1546: 1543: 1540: 1537: 1534: 1531: 1519: 1512: 1505: 1498: 1491: 1485:incompleteness 1461: 1440:, which means 1425: 1422: 1419: 1399: 1396: 1393: 1390: 1358: 1355: 1352: 1304: 1301: 1298: 1278: 1275: 1272: 1269: 1249: 1246: 1243: 1240: 1237: 1209: 1206: 1203: 1200: 1126:For any class 1109:) only if the 1102: 1099: 1030:We define Thm( 1028: 1027: 1016: 1004: 984: 981: 978: 975: 972: 969: 966: 946: 943: 940: 937: 934: 923: 903: 900: 897: 877: 874: 871: 868: 865: 862: 859: 820:is called the 809: 765: 762: 759: 748: 747: 735: 731: 727: 707: 687: 684: 681: 661: 658: 655: 652: 642: 630: 627: 624: 604: 601: 598: 578: 575: 572: 569: 566: 556: 544: 541: 538: 518: 515: 512: 509: 466: 446: 443: 440: 437: 434: 414: 411: 408: 405: 402: 399: 396: 360:. Elements of 333: 330: 327: 324: 321: 301: 298: 285: 282: 279: 276: 273: 270: 267: 256:may be defined 243: 219: 199: 179: 159: 132:Main article: 129: 126: 96:) is a formal 77: 76: 31: 29: 22: 15: 9: 6: 4: 3: 2: 8769: 8758: 8755: 8753: 8750: 8748: 8745: 8743: 8740: 8738: 8735: 8733: 8730: 8729: 8727: 8716: 8715: 8710: 8706: 8701: 8697: 8693: 8692: 8687: 8683: 8679: 8678: 8673: 8669: 8668:"Modal Logic" 8664: 8659: 8658: 8653: 8648: 8644: 8640: 8635: 8634: 8624: 8622:9781134107070 8618: 8614: 8610: 8608: 8601: 8597: 8593: 8592: 8586: 8582: 8576: 8572: 8571: 8565: 8561: 8555: 8551: 8550: 8545: 8541: 8537: 8533: 8527: 8523: 8516: 8512: 8508: 8504: 8498: 8491: 8490: 8482: 8478: 8474: 8463: 8457: 8453: 8452: 8446: 8435: 8429: 8425: 8424: 8418: 8414: 8408: 8403: 8402: 8396: 8392: 8388: 8382: 8378: 8377: 8372: 8368: 8364: 8358: 8354: 8350: 8346: 8342: 8338: 8332: 8329:. Routledge. 8328: 8327: 8322: 8318: 8314: 8310: 8304: 8300: 8299: 8293: 8289: 8283: 8279: 8275: 8270: 8266: 8260: 8256: 8255: 8250: 8245: 8244: 8233: 8229: 8224: 8217: 8212: 8206: 8200: 8193: 8188: 8181: 8175: 8168: 8163: 8156: 8152: 8148: 8145:within which 8144: 8140: 8136: 8132: 8128: 8124: 8120: 8117: 8113: 8109: 8103: 8096: 8091: 8084: 8079: 8069: 8065: 8056: 8053: 8051: 8048: 8046: 8043: 8041: 8038: 8037: 8028: 8025: 8021: 8018: 8014: 8011: 8008: 8003: 8000: 7997: 7993: 7990: 7986: 7982: 7981:Alfred Tarski 7978: 7974: 7970: 7969:Rudolf Carnap 7967: 7966: 7965: 7956: 7953: 7945: 7935: 7931: 7927: 7921: 7920: 7916: 7911:This section 7909: 7905: 7900: 7899: 7891: 7889: 7885: 7881: 7874: 7870: 7866: 7856: 7854: 7853:general frame 7843: 7825: 7822: 7819: 7799: 7796: 7793: 7785: 7782: ∈  7781: 7777: 7770: 7769: 7768: 7766: 7762: 7758: 7754: 7750: 7730: 7727: 7724: 7704: 7701: 7698: 7695: 7675: 7672: 7669: 7666: 7658: 7654: 7650: 7646: 7642: 7638: 7635: 7632: ∈  7631: 7627: 7624: 7621: 7617: 7614: 7613: 7612: 7594: 7591: 7587: 7583: 7580: 7576: 7572: 7569: 7557: 7553: 7550:is a mapping 7534: 7531: 7528: 7525: 7522: 7511: 7507: 7503: 7499: 7495: 7472: 7469: 7466: 7462: 7458: 7453: 7449: 7445: 7442: 7439: 7434: 7430: 7426: 7421: 7417: 7408: 7405: 7395: 7391: 7387: 7384: 7381: 7376: 7372: 7368: 7363: 7359: 7348: 7347: 7346: 7344: 7340: 7324: 7321: 7316: 7312: 7291: 7288: 7285: 7277: 7273: 7269: 7241: 7237: 7233: 7230: 7227: 7222: 7218: 7214: 7209: 7205: 7198: 7195: 7187: 7167: 7164: 7160: 7156: 7153: 7149: 7145: 7142: 7130: 7127: ∈  7123: 7104: 7101: 7098: 7095: 7092: 7081: 7077: 7072: 7070: 7062: 7046: 7042: 7039: 7034: 7031: 7010: 7007: 7004: 6996: 6992: 6991: 6990: 6988: 6980: 6976: 6972: 6969: ∈  6968: 6964: 6960: 6956: 6953: 6949: 6945: 6942: ∈  6941: 6937: 6933: 6929: 6928: 6927: 6925: 6905: 6902: 6898: 6894: 6891: 6864: 6861: 6858: 6847: 6843: 6842:bisimulations 6835: 6819: 6815: 6812: 6805: 6799: 6779: 6776: 6773: 6766: 6765: 6764: 6749: 6746: 6739: 6736: 6733: 6709: 6706: 6702: 6698: 6695: 6691: 6687: 6684: 6657: 6654: 6651: 6648: 6645: 6630: 6626: 6622: 6618: 6614: 6611: ∈  6610: 6606: 6602: 6598: 6594: 6590: 6587: 6583: 6579: 6575: 6571: 6567: 6563: 6560: 6559: 6558: 6543: 6540: 6533: 6530: 6527: 6520:is a mapping 6503: 6500: 6496: 6492: 6489: 6462: 6459: 6456: 6445: 6441: 6437: 6436:homomorphisms 6432: 6430: 6420: 6418: 6414: 6410: 6406: 6396: 6394: 6390: 6386: 6382: 6378: 6374: 6348: 6342: 6336: 6330: 6327: 6324: 6302: 6298: 6294: 6291: 6271: 6268: 6265: 6242: 6233: 6229: 6220: 6217: 6210: 6189: 6183: 6177: 6171: 6168: 6165: 6143: 6139: 6135: 6132: 6109: 6100: 6096: 6087: 6084: 6077: 6059: 6050: 6047: 6039: 6021: 6015: 6012: 6009: 5986: 5980: 5977: 5974: 5954: 5951: 5948: 5925: 5916: 5910: 5904: 5901: 5894: 5876: 5870: 5867: 5864: 5841: 5835: 5832: 5829: 5806: 5797: 5794: 5791: 5785: 5782: 5775: 5757: 5751: 5748: 5745: 5722: 5716: 5713: 5710: 5687: 5678: 5675: 5672: 5666: 5663: 5656: 5653: 5628: 5620: 5616: 5612: 5609: 5606: 5600: 5592: 5588: 5581: 5558: 5547: 5543: 5539: 5536: 5533: 5528: 5524: 5517: 5514: 5511: 5504: 5503: 5502: 5485: 5479: 5476: 5473: 5465: 5458: 5450: 5443: 5436: 5426: 5422: 5418: 5412: ∈  5411: 5401: 5398:and elements 5397: 5393: 5389: 5386: 5379: 5372: 5365: 5362: 5355: 5348: 5347: 5346: 5344: 5341: ≤  5340: 5336: 5333: ∈  5332: 5328: 5324: 5302: 5299: 5296: 5268: 5265: 5262: 5252: 5248: 5241: 5238: 5235: 5232: 5221: 5217: 5213: 5203: 5201: 5196: 5194: 5187: 5183: 5179: 5173: 5169: 5163: 5159: 5155: 5151: 5147: 5143: 5139: 5116: 5113: 5105: 5090: 5087: 5084: 5064: 5061: 5058: 5038: 5035: 5032: 5012: 5006: 5003: 5000: 4993: 4978: 4975: 4972: 4952: 4949: 4946: 4926: 4923: 4920: 4917: 4914: 4907: 4892: 4889: 4886: 4866: 4863: 4860: 4840: 4837: 4834: 4831: 4828: 4821: 4818: 4814: 4798: 4795: 4792: 4772: 4769: 4766: 4746: 4743: 4740: 4732: 4728: 4727: 4726: 4712: 4704: 4685: 4682: 4679: 4653: 4650: 4647: 4644: 4641: 4630: 4625: 4623: 4613: 4596: 4590: 4587: 4584: 4578: 4574: 4570: 4561: 4557: 4553: 4550: 4527: 4522: 4518: 4514: 4511: 4504: 4503: 4502: 4500: 4497: ⊆  4496: 4489: 4470: 4467: 4462: 4459: 4456: 4446: 4442: 4435: 4432: 4429: 4426: 4415: 4414:Carlson model 4411: 4392: 4386: 4383: 4380: 4374: 4368: 4364: 4359: 4352: 4329: 4324: 4320: 4316: 4313: 4306: 4305: 4304: 4302: 4299: ∈  4298: 4294: 4287: 4268: 4265: 4262: 4258: 4253: 4249: 4235: 4225: 4223: 4219: 4215: 4210: 4207: 4205: 4202: 4198: 4194: 4189: 4187: 4183: 4179: 4175: 4171: 4170: 4159: 4153: 4150: 4146: 4143: 4142: 4141: 4139: 4135: 4131: 4126: 4124: 4120: 4114: 4112: 4104: 4100: 4096: 4092: 4088: 4085: 4081: 4078: 4077: 4076: 4074: 4070: 4066: 4061: 4059: 4055: 4051: 4047: 4043: 4039: 4034: 4032: 4028: 4024: 4020: 4016: 4012: 4008: 4004: 4000: 3980: 3977: 3974: 3954: 3951: 3948: 3941: 3926: 3923: 3920: 3900: 3897: 3894: 3891: 3871: 3851: 3847: 3843: 3836: 3835: 3834: 3820: 3812: 3808: 3804: 3800: 3781: 3778: 3775: 3772: 3769: 3758: 3754: 3749: 3747: 3743: 3739: 3735: 3731: 3727: 3723: 3719: 3714: 3712: 3708: 3704: 3700: 3696: 3681: 3678: 3675: 3674: 3671: 3668: 3665: 3662: 3661: 3658: 3657:partial order 3654: 3651: 3648: 3647: 3644: 3640: 3637: 3634: 3631: 3630: 3626: 3623: 3620: 3617: 3616: 3595: 3592: 3589: 3583: 3579: 3575: 3568: 3562: 3559: 3555: 3551: 3544: 3537: 3526: 3523: 3520: 3519: 3516: 3513: 3510: 3507: 3506: 3503: 3500: 3497: 3495: 3492: 3491: 3488: 3485: 3482: 3479: 3478: 3474: 3471: 3468: 3467: 3463: 3460: 3457: 3456: 3452: 3449: 3445: 3441: 3438: 3435: 3434: 3431: 3429: 3425: 3415: 3413: 3394: 3388: 3385: 3362: 3342: 3339: 3331: 3326: 3324: 3320: 3304: 3301: 3292: 3289: 3283: 3277: 3268: 3260: 3256: 3232: 3228: 3224: 3214: 3207: 3196: 3179: 3159: 3156: 3149: 3146: 3145: 3141: 3125: 3102: 3098: 3094: 3090: 3087: 3080: 3069: 3055: 3052: 3046: 3043: 3036: 3033: 3032: 3017: 3014: 3011: 3005: 3001: 2997: 2994: 2991: 2987: 2983: 2975: 2972: 2958: 2955: 2949: 2946: 2939: 2936: 2935: 2920: 2917: 2914: 2908: 2904: 2900: 2892: 2878: 2875: 2869: 2862: 2859: 2858: 2840: 2836: 2832: 2829: 2826: 2822: 2818: 2811: 2802: 2798: 2794: 2791: 2788: 2784: 2780: 2772: 2758: 2755: 2752: 2746: 2743: 2740: 2733: 2730: 2729: 2725: 2721: 2707: 2704: 2701: 2695: 2692: 2689: 2682: 2679: 2678: 2663: 2659: 2655: 2652: 2649: 2645: 2641: 2635: 2631: 2627: 2624: 2621: 2617: 2613: 2606: 2589: 2583: 2580: 2574: 2571: 2565: 2559: 2556: 2550: 2543: 2540: 2539: 2535: 2531: 2528: 2514: 2505: 2496: 2493: 2487: 2481: 2475: 2468: 2465: 2464: 2461: 2458: 2454: 2451: 2437: 2434: 2425: 2419: 2416: 2410: 2403: 2400: 2399: 2384: 2380: 2376: 2370: 2366: 2362: 2359: 2356: 2352: 2348: 2340: 2337: 2323: 2320: 2317: 2311: 2308: 2301: 2298: 2297: 2282: 2278: 2274: 2268: 2264: 2260: 2252: 2249: 2235: 2229: 2226: 2223: 2203: 2200: 2197: 2191: 2184: 2181: 2180: 2162: 2158: 2154: 2147: 2140: 2129: 2126: 2109: 2083: 2063: 2060: 2054: 2051: 2044: 2041: 2040: 2025: 2021: 2017: 2011: 2007: 2003: 2000: 1997: 1993: 1989: 1981: 1978: 1964: 1961: 1958: 1952: 1949: 1942: 1939: 1938: 1920: 1916: 1912: 1909: 1906: 1902: 1898: 1891: 1882: 1878: 1874: 1866: 1863: 1849: 1846: 1840: 1837: 1834: 1827: 1824: 1823: 1808: 1804: 1800: 1792: 1789: 1775: 1769: 1766: 1759: 1756: 1755: 1751: 1734: 1731: 1725: 1722: 1710: 1704: 1698: 1691: 1688: 1687: 1683: 1680: 1677: 1676: 1673: 1671: 1667: 1663: 1659: 1656:; and axioms 1655: 1651: 1647: 1646:deontic logic 1643: 1639: 1635: 1631: 1627: 1623: 1613: 1599: 1596: 1593: 1587: 1584: 1576: 1572: 1556: 1553: 1544: 1541: 1535: 1529: 1518: 1511: 1504: 1497: 1494: ⊆  1490: 1486: 1482: 1477: 1475: 1459: 1451: 1447: 1443: 1439: 1423: 1420: 1417: 1397: 1394: 1391: 1388: 1380: 1376: 1372: 1356: 1353: 1350: 1342: 1338: 1335: ∈  1334: 1330: 1326: 1322: 1318: 1302: 1299: 1296: 1276: 1273: 1270: 1267: 1244: 1241: 1238: 1227: 1223: 1207: 1201: 1198: 1190: 1185: 1183: 1179: 1176:is sound wrt 1175: 1171: 1167: 1163: 1159: 1155: 1152: 1147: 1145: 1141: 1137: 1133: 1129: 1124: 1122: 1118: 1117: 1112: 1108: 1098: 1096: 1092: 1088: 1084: 1083: 1078: 1074: 1070: 1066: 1062: 1061: 1056: 1051: 1049: 1045: 1041: 1037: 1033: 1025: 1021: 1017: 1002: 979: 976: 973: 970: 967: 941: 938: 935: 924: 921: 918: ∈  917: 901: 898: 895: 872: 869: 866: 863: 860: 849: 848: 847: 845: 841: 836: 834: 832: 827: 823: 807: 799: 795: 791: 787: 783: 779: 763: 760: 757: 733: 729: 725: 705: 685: 682: 679: 659: 656: 653: 650: 643: 628: 625: 622: 602: 599: 596: 576: 570: 567: 564: 557: 542: 539: 536: 516: 510: 507: 500: 499: 498: 496: 492: 488: 485: ∈  484: 480: 464: 441: 438: 435: 409: 406: 403: 400: 397: 386: 381: 379: 375: 371: 367: 363: 359: 355: 351: 347: 328: 325: 322: 311: 307: 297: 283: 277: 271: 268: 265: 257: 241: 233: 217: 197: 149: 145: 141: 135: 125: 123: 119: 115: 111: 107: 103: 99: 95: 91: 87: 83: 73: 70: 62: 52: 48: 42: 41: 35: 30: 21: 20: 8752:Sheaf theory 8737:Model theory 8712: 8689: 8675: 8656: 8643:the original 8612: 8606: 8590: 8569: 8552:. Springer. 8548: 8521: 8488: 8465:. Retrieved 8450: 8437:. Retrieved 8422: 8400: 8375: 8352: 8325: 8321:Hughes, G.E. 8297: 8277: 8253: 8249:de Rijke, M. 8231: 8228:Stokhof 2008 8223: 8211: 8199: 8192:Simpson 1994 8187: 8174: 8162: 8154: 8150: 8146: 8142: 8138: 8134: 8130: 8126: 8122: 8118: 8115: 8111: 8107: 8102: 8090: 8078: 8068: 7992:Arthur Prior 7972: 7963: 7948: 7942:October 2009 7939: 7924:Please help 7912: 7882:, they give 7876: 7849: 7841: 7783: 7779: 7771: 7764: 7756: 7752: 7748: 7746: 7656: 7652: 7648: 7644: 7640: 7633: 7629: 7625: 7615: 7555: 7551: 7509: 7505: 7497: 7496: 7493: 7342: 7338: 7275: 7271: 7260: 7185: 7128: 7121: 7079: 7073: 7068: 7066: 7060: 6994: 6984: 6978: 6974: 6970: 6966: 6962: 6958: 6951: 6947: 6943: 6939: 6935: 6931: 6923: 6846:bisimulation 6845: 6839: 6833: 6634: 6628: 6624: 6620: 6616: 6612: 6608: 6604: 6600: 6596: 6592: 6585: 6581: 6577: 6573: 6569: 6565: 6561: 6443: 6439: 6434:The natural 6433: 6429:model theory 6426: 6416: 6413:topos theory 6405:sheaf theory 6402: 6392: 6388: 6384: 6380: 6376: 6372: 6370: 5648: 5460: 5456: 5454: 5445: 5438: 5431: 5424: 5420: 5413: 5406: 5399: 5395: 5391: 5381: 5374: 5367: 5357: 5350: 5342: 5338: 5334: 5330: 5326: 5319: 5222:is a triple 5219: 5211: 5209: 5197: 5192: 5185: 5177: 5171: 5167: 5161: 5157: 5153: 5149: 5145: 5141: 5137: 5135: 4817:monotonicity 4812: 4730: 4631:is a triple 4628: 4626: 4619: 4611: 4498: 4491: 4487: 4413: 4407: 4300: 4296: 4289: 4285: 4237: 4221: 4217: 4211: 4208: 4190: 4185: 4181: 4174:decidability 4167: 4165: 4157: 4140:) such that 4127: 4122: 4118: 4115: 4108: 4102: 4098: 4094: 4090: 4083: 4079: 4072: 4068: 4064: 4062: 4057: 4053: 4049: 4045: 4041: 4037: 4035: 4030: 4026: 4022: 4018: 4015:Zorn's lemma 4010: 4006: 4002: 3998: 3996: 3810: 3806: 3802: 3798: 3756: 3752: 3750: 3745: 3741: 3737: 3733: 3729: 3725: 3721: 3717: 3715: 3702: 3698: 3694: 3692: 3638:GL or 4, GL 3427: 3423: 3421: 3329: 3327: 3319:modus ponens 3257:can also be 3254: 3252: 2773:convergent: 2724:second-order 2533: 2529: 2460:well-founded 2456: 2455:transitive, 2452: 1661: 1657: 1649: 1641: 1629: 1621: 1619: 1574: 1570: 1516: 1509: 1502: 1495: 1488: 1484: 1480: 1478: 1473: 1449: 1445: 1441: 1437: 1378: 1374: 1370: 1343:as follows: 1340: 1336: 1332: 1328: 1324: 1320: 1316: 1221: 1188: 1186: 1181: 1177: 1173: 1169: 1165: 1161: 1157: 1153: 1150: 1148: 1139: 1131: 1127: 1125: 1121:derivability 1120: 1114: 1104: 1094: 1090: 1086: 1080: 1076: 1072: 1068: 1064: 1058: 1054: 1052: 1047: 1043: 1039: 1035: 1031: 1029: 1023: 1019: 919: 915: 843: 839: 837: 829: 825: 821: 797: 793: 789: 785: 781: 777: 749: 494: 490: 486: 482: 478: 387:is a triple 385:Kripke model 384: 382: 373: 369: 365: 361: 357: 349: 345: 309: 306:Kripke frame 305: 303: 137: 122:model theory 114:modal logics 89: 85: 81: 80: 65: 56: 37: 8732:Modal logic 8467:24 December 8439:24 December 8298:Modal Logic 8254:Modal Logic 8002:Stig Kanger 7855:semantics. 7558:to a model 7080:unravelling 6440:p-morphisms 5437:) holds in 5216:first-order 4813:persistency 4197:unravelling 4149:first-order 4130:undecidable 4001:, as every 3649:Grz, S4Grz 3475:transitive 3453:all frames 1666:C. I. Lewis 1634:truth axiom 1626:Saul Kripke 1577:-tautology 1154:corresponds 364:are called 310:modal frame 148:connectives 134:Modal logic 110:André Joyal 106:Saul Kripke 51:introducing 8726:Categories 8594:(Thesis). 8531:1904987206 8461:019875244X 8241:References 8155:as a whole 8131:a model of 8023:community; 7620:surjection 7611:such that 7498:Filtration 7259:such that 6973:such that 6946:such that 6615:such that 6557:such that 6387:the value 6284:and every 6158:such that 5152:such that 4703:preordered 4232:See also: 4193:filtration 4151:definable, 4101:satisfies 3722:consistent 3527:preorder, 3464:reflexive 3428:correspond 3070:function: 2893:discrete: 2726:property) 1980:transitive 1119:relation ( 838:A formula 826:evaluation 780:satisfies 718:such that 312:is a pair 59:April 2013 34:references 8696:EMS Press 8607:Tractatus 8546:(2012) . 8513:(2006b). 8479:(2006a). 8347:(2013) . 8323:(2012) . 8135:formula F 7913:does not 7823:⊩ 7797:⊩ 7728:⊩ 7702:∈ 7696:◻ 7673:◻ 7670:⊩ 7599:⟩ 7592:⊩ 7566:⟨ 7538:⟩ 7535:⊩ 7520:⟨ 7478:⟩ 7443:… 7414:⟨ 7401:⟩ 7385:… 7356:⟨ 7322:⊩ 7289:⊩ 7247:⟩ 7231:… 7202:⟨ 7172:⟩ 7165:⊩ 7139:⟨ 7108:⟩ 7105:⊩ 7090:⟨ 7040:⊩ 7008:⊩ 6910:⟩ 6888:⟨ 6868:⟩ 6856:⟨ 6813:⊩ 6777:⊩ 6743:→ 6737:: 6714:⟩ 6707:⊩ 6681:⟨ 6661:⟩ 6658:⊩ 6643:⟨ 6591:whenever 6537:→ 6531:: 6508:⟩ 6486:⟨ 6466:⟩ 6454:⟨ 6346:→ 6328:⊩ 6295:∈ 6269:≥ 6227:∀ 6221:⊩ 6187:→ 6169:⊩ 6136:∈ 6094:∃ 6088:⊩ 6054:⊥ 6051:⊩ 6013:⊩ 5978:⊩ 5952:≥ 5914:→ 5905:⊩ 5868:⊩ 5833:⊩ 5795:∨ 5786:⊩ 5749:⊩ 5714:⊩ 5676:∧ 5667:⊩ 5647:holds in 5610:… 5537:… 5515:⊩ 5477:⊩ 5390:for each 5306:⟩ 5303:≤ 5294:⟨ 5274:⟩ 5266:∈ 5239:≤ 5230:⟨ 5120:⊥ 5117:⊩ 5088:⊩ 5062:⊩ 5036:≥ 5010:→ 5004:⊩ 4976:⊩ 4950:⊩ 4924:∨ 4918:⊩ 4890:⊩ 4864:⊩ 4838:∧ 4832:⊩ 4796:⊩ 4770:⊩ 4744:≤ 4713:⊩ 4689:⟩ 4686:≤ 4677:⟨ 4657:⟩ 4654:⊩ 4648:≤ 4639:⟨ 4588:⊩ 4582:⇒ 4554:∈ 4548:∀ 4519:◻ 4515:⊩ 4474:⟩ 4471:⊩ 4460:∈ 4424:⟨ 4384:⊩ 4378:⇒ 4350:∀ 4321:◻ 4317:⊩ 4295:for each 4266:∈ 4259:∣ 4250:◻ 4069:canonical 3978:∈ 3952:⊩ 3924:∈ 3898:∈ 3892:◻ 3821:⊩ 3785:⟩ 3782:⊩ 3767:⟨ 3627:preorder 3587:⇒ 3566:∀ 3563:∧ 3542:∃ 3535:∀ 3398:⊤ 3395:◊ 3392:→ 3386:◊ 3366:⊤ 3363:◊ 3340:◊ 3302:◻ 3299:→ 3290:∧ 3281:→ 3269:◻ 3259:rewritten 3219:¬ 3212:∀ 3205:∀ 3183:⊥ 3180:◻ 3157:◻ 3123:∃ 3085:∃ 3078:∀ 3053:◻ 3050:↔ 3044:◊ 3009:⇒ 2995:∧ 2956:◻ 2953:→ 2947:◊ 2912:⇒ 2876:◻ 2873:→ 2830:∧ 2809:∃ 2806:⇒ 2792:∧ 2756:◊ 2753:◻ 2750:→ 2744:◻ 2741:◊ 2705:◻ 2702:◊ 2699:→ 2693:◊ 2690:◻ 2653:∨ 2639:⇒ 2625:∧ 2587:→ 2581:◻ 2575:◻ 2572:∨ 2563:→ 2557:◻ 2551:◻ 2512:→ 2503:→ 2494:◻ 2491:→ 2482:◻ 2476:◻ 2435:◻ 2432:→ 2423:→ 2417:◻ 2411:◻ 2374:⇒ 2360:∧ 2339:Euclidean 2321:◊ 2318:◻ 2315:→ 2309:◊ 2272:⇒ 2253: : 2251:symmetric 2233:→ 2227:◻ 2224:◊ 2201:◊ 2198:◻ 2195:→ 2145:∃ 2138:∀ 2113:⊥ 2110:◻ 2107:¬ 2087:⊤ 2084:◊ 2061:◊ 2058:→ 2052:◻ 2015:⇒ 2001:∧ 1962:◻ 1959:◻ 1956:→ 1950:◻ 1910:∧ 1889:∃ 1886:⇒ 1847:◻ 1844:→ 1838:◻ 1835:◻ 1791:reflexive 1773:→ 1767:◻ 1732:◻ 1729:→ 1723:◻ 1717:→ 1708:→ 1699:◻ 1597:◻ 1594:◻ 1591:→ 1585:◻ 1554:◻ 1551:→ 1542:◻ 1539:↔ 1530:◻ 1460:⊩ 1421:⊩ 1395:◻ 1392:⊩ 1354:⊩ 1300:⊩ 1274:◻ 1271:⊩ 1248:⟩ 1236:⟨ 1226:reflexive 1205:→ 1199:◻ 1003:⊩ 983:⟩ 980:⊩ 965:⟨ 945:⟩ 933:⟨ 899:⊩ 876:⟩ 873:⊩ 858:⟨ 808:⊩ 761:⊩ 683:⊩ 657:◻ 654:⊩ 626:⊩ 600:⊮ 574:→ 568:⊩ 540:⊮ 514:¬ 511:⊩ 465:⊩ 445:⟩ 433:⟨ 413:⟩ 410:⊩ 395:⟨ 332:⟩ 320:⟨ 281:¬ 278:◻ 275:¬ 266:◊ 242:◻ 218:◊ 198:◻ 178:¬ 158:→ 98:semantics 8397:(1969). 8373:(2000). 8034:See also 7772:u ≡ 7761:quotient 7688:, where 7595:′ 7584:′ 7573:′ 7409:′ 7270:for all 7184:, where 7168:′ 7157:′ 7146:′ 7043:′ 7035:′ 6906:′ 6895:′ 6816:′ 6750:′ 6710:′ 6699:′ 6688:′ 6568:implies 6544:′ 6504:′ 6493:′ 6002:implies 5286:, where 5077:implies 4669:, where 4216:, and a 4201:cut-free 3797:, where 3679:D, 4, 5 3625:directed 3621:T, 4, G 3524:T, 4, M 3511:T, 4, H 3487:preorder 1648:; axiom 1640:; axiom 1628:; axiom 1191: : 1082:complete 1018:a class 925:a frame 914:for all 850:a model 833:relation 750:We read 698:for all 425:, where 344:, where 8711:(ed.). 8698:, 2001 8674:(ed.). 8112:differs 7976:Tarski; 7934:removed 7919:sources 7776: v 7717:, then 7647:)  6997:, then 6599:)  6576:)  5180:→ ⊥ is 5170:, then 4785:, then 4111:compact 4017:, each 3655:finite 3641:finite 3197:empty: 3138:is the 1515:. Then 1410:, thus 1381:. Then 1289:, then 1134:) is a 831:forcing 796:forces 792:”, or “ 47:improve 8619:  8577:  8556:  8528:  8499:  8458:  8430:  8409:  8383:  8359:  8333:  8305:  8284:  8261:  8178:After 8151:within 8108:notion 8016:proof; 7871:, and 7659:) and 7651:  7278:, and 7078:using 6603:  6580:  5160:, not 4759:, and 4218:finite 3670:serial 3635:, K4W 3439:Axioms 3253:Axiom 2128:serial 1448:  1444:  1377:  1373:  1323:  1319:  1315:since 1228:frame 372:, and 370:worlds 36:, but 8707:. In 8670:. In 8518:(PDF) 8493:(PDF) 8484:(PDF) 8061:Notes 8007:Lewis 7988:time. 7618:is a 7554:from 6371:Here 5430:,..., 5419:: if 5405:,..., 5214:be a 5184:, so 4701:is a 4054:frame 4013:. By 3913:then 3884:, if 3618:S4.2 3521:S4.1 3508:S4.3 3483:T, 4 3321:as a 1865:dense 1681:Axiom 1260:: if 1160:, if 1067:, if 1060:sound 888:, if 844:valid 828:, or 366:nodes 352:is a 8617:ISBN 8575:ISBN 8554:ISBN 8526:ISBN 8497:ISBN 8469:2014 8456:ISBN 8441:2014 8428:ISBN 8407:ISBN 8381:ISBN 8357:ISBN 8331:ISBN 8303:ISBN 8282:ISBN 8259:ISBN 8133:the 7917:any 7915:cite 7851:the 7076:tree 6977:and 6961:and 6950:and 6934:and 6880:and 6673:and 6619:and 6478:and 6411:in 6040:not 5738:and 5373:and 5210:Let 5106:not 4879:and 4412:. A 4222:S4.3 4123:K4.1 4119:S4.1 3813:and 3751:The 3732:(an 3676:D45 3436:Name 2466:Grz 1678:Name 1660:and 1085:wrt 846:in: 784:”, “ 776:as “ 493:and 254:and 232:dual 170:and 108:and 100:for 8147:any 8139:not 8119:has 7928:by 7763:of 7639:if 7502:FMP 7267:i+1 7069:all 6993:if 6957:if 6930:if 5857:or 5140:, ¬ 4965:or 4819:)), 4729:if 4627:An 4195:or 4046:not 4027:MCS 4007:MCS 3807:MCS 3755:of 3738:MCS 3480:S4 3469:K4 3261:as 3172:or 2976:: 2401:GL 2216:or 2099:or 2076:or 1636:in 1436:by 1097:). 1089:if 1079:is 1075:). 1057:is 842:is 615:or 368:or 356:on 308:or 234:of 142:of 88:or 8728:: 8694:, 8688:, 8654:. 8542:; 8319:; 8234:.. 7867:, 7786:, 7649:R’ 7343:R’ 7186:W’ 6989:: 6944:W’ 6940:v’ 6631:’. 6601:R’ 6588:), 6578:R’ 6395:. 6317:, 5967:, 5501:: 5345:: 5202:. 5195:. 5156:≤ 5051:, 4113:. 4060:. 3666:D 3663:D 3633:GL 3494:S5 3472:4 3461:T 3458:T 3450:— 3447:K 3414:. 3332:, 3147:- 3142:) 3034:- 2937:- 2860:- 2731:G 2680:M 2541:H 2341:: 2299:5 2182:B 2130:: 2042:D 1982:: 1940:4 1867:: 1825:- 1793:: 1757:T 1689:K 1672:. 1612:. 1575:GL 1571:GL 1472:. 1220:. 1146:. 1050:. 824:, 497:: 383:A 380:. 304:A 272::= 8717:. 8680:. 8625:. 8598:. 8583:. 8562:. 8534:. 8505:. 8471:. 8443:. 8415:. 8389:. 8365:. 8339:. 8311:. 8290:. 8267:. 8218:. 8182:. 8169:. 8127:F 8123:F 8116:F 8085:. 7955:) 7949:( 7944:) 7940:( 7936:. 7922:. 7838:. 7826:A 7820:v 7800:A 7794:u 7784:X 7780:A 7774:X 7765:W 7757:f 7753:X 7749:f 7743:. 7731:A 7725:v 7705:X 7699:A 7676:A 7667:u 7657:v 7655:( 7653:f 7645:u 7643:( 7641:f 7636:, 7634:X 7630:p 7626:f 7622:, 7616:f 7588:, 7581:R 7577:, 7570:W 7556:W 7552:f 7532:, 7529:R 7526:, 7523:W 7510:X 7506:X 7490:, 7473:1 7470:+ 7467:n 7463:w 7459:, 7454:n 7450:w 7446:, 7440:, 7435:1 7431:w 7427:, 7422:0 7418:w 7406:R 7396:n 7392:w 7388:, 7382:, 7377:1 7373:w 7369:, 7364:0 7360:w 7339:p 7325:p 7317:n 7313:w 7292:p 7286:s 7276:n 7272:i 7263:i 7261:w 7242:n 7238:w 7234:, 7228:, 7223:1 7219:w 7215:, 7210:0 7206:w 7199:= 7196:s 7161:, 7154:R 7150:, 7143:W 7129:W 7125:0 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5908:( 5902:w 5892:, 5880:] 5877:e 5874:[ 5871:B 5865:w 5845:] 5842:e 5839:[ 5836:A 5830:w 5810:] 5807:e 5804:[ 5801:) 5798:B 5792:A 5789:( 5783:w 5773:, 5761:] 5758:e 5755:[ 5752:B 5746:w 5726:] 5723:e 5720:[ 5717:A 5711:w 5691:] 5688:e 5685:[ 5682:) 5679:B 5673:A 5670:( 5664:w 5654:, 5651:w 5649:M 5635:) 5632:] 5629:e 5626:[ 5621:n 5617:t 5613:, 5607:, 5604:] 5601:e 5598:[ 5593:1 5589:t 5585:( 5582:P 5562:] 5559:e 5556:[ 5553:) 5548:n 5544:t 5540:, 5534:, 5529:1 5525:t 5521:( 5518:P 5512:w 5489:] 5486:e 5483:[ 5480:A 5474:w 5463:w 5461:M 5457:e 5451:. 5448:v 5446:M 5441:u 5439:M 5434:n 5432:a 5428:1 5425:a 5423:( 5421:P 5416:u 5414:M 5409:n 5407:a 5403:1 5400:a 5396:P 5392:n 5387:, 5384:u 5382:M 5377:v 5375:M 5370:u 5368:M 5363:, 5360:v 5358:M 5353:u 5351:M 5343:v 5339:u 5335:W 5331:w 5327:L 5322:w 5320:M 5300:, 5297:W 5269:W 5263:w 5259:} 5253:w 5249:M 5245:{ 5242:, 5236:, 5233:W 5220:L 5212:L 5193:A 5191:¬ 5189:⊩ 5186:w 5178:A 5175:⊩ 5172:w 5168:A 5165:⊩ 5162:u 5158:u 5154:w 5150:u 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Index

references
inline citations
improve
introducing
Learn how and when to remove this message
possible world semantics
semantics
non-classical logic
Saul Kripke
André Joyal
modal logics
intuitionistic logic
model theory
Modal logic
countably infinite set
propositional variables
connectives
dual
may be defined
binary relation
accessibility relation
forcing
sound
complete
derivation system
semantic consequence
syntactic consequence
normal modal logic
Japaridze's polymodal logic
reflexive

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