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Given a variety V of algebras we provide an axiomatization of the class of
complex algebras of the algebras in V. This axiomatization can be obtained
effectively from an axiomatization of V; in fact, it is recursive if the
axiomatization of V is given as a recursive enumeration.
Keyword(s): Bo...
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Chu spaces are a new model for information structure (cf. J. Barwise &
J. Seligman, "Information Flow", Cambridge UP, 1997) and for mathematical
structure in general (cf. Vaughan Pratt's ongoing work at the homepage
http://boole.stanford.edu/live). Their properties are usually developed
as a ...
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The problem of interpolation for countable infinitary graded modal logics
is considered. Pairs of formulae having an interpolant in these logics
are characterized semantically using generalized consistency property.
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We review the various explanations that have been offered to account for
subjects' behaviour in Wason's famous selection task.
We argue that one element that is lacking is a good understanding of
subjects' semantics for the key expressions involved, and an understanding
of how this semantics ...
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This note exploits back-and-forth characteristics to
construct, using a single method, short proofs for ten
classics of first-order and modal logic:
interpolation theorems, preservation theorems, and
Lindstroem's theorem.
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In \cite{iemhoff} we gave a countable basis $\cal V$ for the
admissible rules of $\ipc$. Here we show that there is no proper
superintuitionistic logic with the disjunction property for which all
rules in $\cal V$ are admissible.
This shows that, relative to the disjunction property, $\ipc$ is
ma...
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In their simplest form, hybrid languages are propositional modal
languages which can refer to states. They were introduced by Arthur
Prior, the inventor of tense logic, and played an important role in
his work: because they make reference to specific times possible, they
remove the most serious o...
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Message passing by means of public key encryption is described in
terms of doxastic dynamic logic. A secret message from agent A to
agent B can have as effect that B learns something new from A, but it
can also cause a change in the real world, when the contents of the
message forces B to cease t...
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This chapter is about the satisfiability problem for modal logics and
related formalisms. We discuss and explain the good computational
behaviour of many modal systems. We show how finite and other simple
structures are used in the proofs of various decidability and
complexity results. In doing...
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This is the first part of the whole work which will consist of two
parts and intends to obtain a clear picture of the lattice
$\Lambda({\bf Df}_2)$ of all subvarieties of the variety {\bf Df}$_2$
of the two-dimensional diagonal-free cylindric algebras. Here we show
that every proper subvariety of...
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The guarded fragment (GF) was introduced by Andreka, van Benthem and
Nemeti as a fine-structure of first order logic which combines a great
expressive power with nice modal behavior. It consists of relational
first order formulas whose quantifiers are relativized by atoms in a
certain way. Sligh...