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Modal Languages And Bounded Fragments Of Predicate Logic
, 1996
"... Model Theory. These are nonempty families I of partial isomorphisms between models M and N , closed under taking restrictions to smaller domains, and satisfying the usual BackandForth properties for extension with objects on either side  restricted to apply only to partial isomorphisms of size ..."
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Cited by 271 (12 self)
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Model Theory. These are nonempty families I of partial isomorphisms between models M and N , closed under taking restrictions to smaller domains, and satisfying the usual BackandForth properties for extension with objects on either side  restricted to apply only to partial isomorphisms of size at most k . 'Invariance for kpartial isomorphism' means having the same truth value at tuples of objects in any two models that are connected by a partial isomorphism in such a set. The precise sense of this is spelt out in the following proof. 21 Proof (Outline.) kvariable formulas are preserved under partial isomorphism, by a simple induction. More precisely, one proves, for any assignment A and any partial isomorphism IÎI which is defined on the Avalues for all variables x 1 , ..., x k , that M, A = f iff N , IoA = f . The crucial step in the induction is the quantifier case. Quantified variables are irrelevant to the assignment, so that the relevant partial isomorphism can be res...
A Tutorial on (Co)Algebras and (Co)Induction
 EATCS Bulletin
, 1997
"... . Algebraic structures which are generated by a collection of constructors like natural numbers (generated by a zero and a successor) or finite lists and trees are of wellestablished importance in computer science. Formally, they are initial algebras. Induction is used both as a definition pr ..."
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Cited by 269 (36 self)
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. Algebraic structures which are generated by a collection of constructors like natural numbers (generated by a zero and a successor) or finite lists and trees are of wellestablished importance in computer science. Formally, they are initial algebras. Induction is used both as a definition principle, and as a proof principle for such structures. But there are also important dual "coalgebraic" structures, which do not come equipped with constructor operations but with what are sometimes called "destructor" operations (also called observers, accessors, transition maps, or mutators). Spaces of infinite data (including, for example, infinite lists, and nonwellfounded sets) are generally of this kind. In general, dynamical systems with a hidden, blackbox state space, to which a user only has limited access via specified (observer or mutator) operations, are coalgebras of various kinds. Such coalgebraic systems are common in computer science. And "coinduction" is the appropriate te...
Vertical Bisimulation
, 1998
"... We investigate criteria to relate specifications and implementations belonging to conceptually dfferent abstraction levels, and we propose vertical bisimulation as a candidate relation for this purpose. Vertical bisimulation is indexed by a function mapping abstract actions onto concrete processes, ..."
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bisimulation satisfies a number of congruencelike proof rules (notably a structural one for recursion) that offer a powerful, compositional proof technique to verify whether a certain process is an implementation for some speci cation. We give a number of small examples to demonstrate the advantages
A Theory of Bisimulation for the picalculus
, 1993
"... We study a new formulation of bisimulation for the calculus [MPW92], which we have called open bisimulation ( ). In contrast with the previously known bisimilarity equivalences, is preserved by all calculus operators, including input prefix. The differences among all these equivalences alread ..."
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Cited by 66 (0 self)
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already appear in the sublanguage without name restrictions: Here the definition of can be factorised into a "standard" part which, modulo the different syntax of actions, is the CCS bisimulation, and a part specific to the calculus, which requires name instantiation. Attractive features
On the Origins of Bisimulation and
"... Bisimulation and bisimilarity are coinductive notions, and as such are intimately related to fixed points, in particular greatest fixed points. Therefore also the appearance of coinduction and fixed points is discussed, though in this case only within Computer Science. The paper ends with some histo ..."
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Bisimulation and bisimilarity are coinductive notions, and as such are intimately related to fixed points, in particular greatest fixed points. Therefore also the appearance of coinduction and fixed points is discussed, though in this case only within Computer Science. The paper ends with some
A Foundation for Actor Computation
 Journal of Functional Programming
, 1998
"... We present an actor language which is an extension of a simple functional language, and provide a precise operational semantics for this extension. Actor configurations represent open distributed systems, by which we mean that the specification of an actor system explicitly takes into account the in ..."
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Cited by 257 (51 self)
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We present an actor language which is an extension of a simple functional language, and provide a precise operational semantics for this extension. Actor configurations represent open distributed systems, by which we mean that the specification of an actor system explicitly takes into account the interface with external components. We study the composability of such systems. We define and study various notions of testing equivalence on actor expressions and configurations. The model we develop provides fairness. An important result is that the three forms of equivalence, namely, convex, must, and may equivalences, collapse to two in the presence of fairness. We further develop methods for proving laws of equivalence and provide example proofs to illustrate our methodology.
Split and ST bisimulation semantics
 Information and Computation
"... In this paper the notion of action atomicity is relaxed by permitting actions to be observed in the middle of their evolution. Non atomic semantic equivalences, based on the notion of bisimulation, are studied over stable event structures. Splitn bisimulation equivalence (denoted n ¸) considers ea ..."
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Cited by 13 (3 self)
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In this paper the notion of action atomicity is relaxed by permitting actions to be observed in the middle of their evolution. Non atomic semantic equivalences, based on the notion of bisimulation, are studied over stable event structures. Splitn bisimulation equivalence (denoted n ¸) considers
Bisimulations on Planet
 University of Amsterdam
, 1999
"... institute for logic, language and computation For further information about ILLCpublications, please contact ..."
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Cited by 2 (0 self)
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institute for logic, language and computation For further information about ILLCpublications, please contact
Analysis of Timed Systems using TimeAbstracting Bisimulations
 Formal Methods in System Design
, 1999
"... ing Bisimulations Stavros Tripakis and Sergio Yovine February 5, 1999 Abstract The objective of this paper is to show how verification of densetime systems modeled as timed automata can be performed using classical (i.e. untimed) verification techniques. In that way, the existing rich infrastruc ..."
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Cited by 72 (12 self)
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ing Bisimulations Stavros Tripakis and Sergio Yovine February 5, 1999 Abstract The objective of this paper is to show how verification of densetime systems modeled as timed automata can be performed using classical (i.e. untimed) verification techniques. In that way, the existing rich
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