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49
Generic trace semantics via coinduction
 Logical Methods in Comp. Sci
, 2007
"... Abstract. Trace semantics has been defined for various kinds of statebased systems, notably with different forms of branching such as nondeterminism vs. probability. In this paper we claim to identify one underlying mathematical structure behind these “trace ..."
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Cited by 17 (6 self)
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Abstract. Trace semantics has been defined for various kinds of statebased systems, notably with different forms of branching such as nondeterminism vs. probability. In this paper we claim to identify one underlying mathematical structure behind these “trace
From Settheoretic Coinduction to Coalgebraic Coinduction: some results, some problems
, 1999
"... ..."
NonDeterministic Kleene Coalgebras
"... In this paper, we present a systematic way of deriving (1) languages of (generalised) regular expressions, and (2) sound and complete axiomatizations thereof, for a wide variety of systems. This generalizes both the results of Kleene (on regular languages and deterministic finite automata) and Miln ..."
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Cited by 15 (4 self)
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In this paper, we present a systematic way of deriving (1) languages of (generalised) regular expressions, and (2) sound and complete axiomatizations thereof, for a wide variety of systems. This generalizes both the results of Kleene (on regular languages and deterministic finite automata) and Milner (on regular behaviours and finite labelled transition systems), and includes many other systems such as Mealy and Moore machines.
Components as processes: An exercise in coalgebraic modeling
 FMOODS’2000  Formal Methods for Open ObjectOriented Distributed Systems
, 2000
"... Abstract Software components, arising, typically, in systems ’ analysis and design, are characterized by a public interface and a private encapsulated state. They persist (and evolve) in time, according to some behavioural patterns. This paper is an exercise in modeling such components as coalgebras ..."
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Cited by 14 (6 self)
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Abstract Software components, arising, typically, in systems ’ analysis and design, are characterized by a public interface and a private encapsulated state. They persist (and evolve) in time, according to some behavioural patterns. This paper is an exercise in modeling such components as coalgebras for some kinds of endofunctors on ¢¡¤ £ , capturing both (interface) types and behavioural aspects. The construction of component categories, cofibred over the interface space, emerges by generalizing the usual notion of a coalgebra morphism. A collection of composition operators as well as a generic notion of bisimilarity, are discussed.
Invariants, Bisimulations and the Correctness of Coalgebraic Refinements
 Techn. Rep. CSIR9704, Comput. Sci. Inst., Univ. of Nijmegen
, 1997
"... . Coalgebraic specifications are used to formally describe the behaviour of classes in objectoriented languages. In this paper, a general notion of refinement between two such coalgebraic specifications is defined, capturing the idea that one "concrete" class specification realises the behaviour of ..."
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Cited by 12 (4 self)
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. Coalgebraic specifications are used to formally describe the behaviour of classes in objectoriented languages. In this paper, a general notion of refinement between two such coalgebraic specifications is defined, capturing the idea that one "concrete" class specification realises the behaviour of the other, "abstract" class specification. Two (complete) prooftechniques are given to establish such refinements: one involving an invariant (a predicate that is closed under transitions) on the concrete class, and one involving a bisimulation (a relation that is closed under transitions) between the concrete and the abstract class. The latter can only be used if the abstract class is what we call totally specified. Parts of the underlying theory of invariants and bisimulations in a coalgebraic setting are included, involving least and greatest invariants and connections between invariants and bisimulations. Also, the proofprinciples are illustrated in examples (which are fully formalise...
Coalgebraic Reasoning about Classes in ObjectOriented Languages
 In Coalgebraic Methods in Computer Science, number 11. Electronic Notes in Computer Science
, 1998
"... This note briefly discusses how some of the ideas developed in the theory of coalgebras are used in a frontend tool called LOOP, developed jointly in Dresden and Nijmegen, for reasoning (with a backend theorem prover) about classes in objectoriented languages. It will describe reasoning both about ..."
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Cited by 10 (0 self)
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This note briefly discusses how some of the ideas developed in the theory of coalgebras are used in a frontend tool called LOOP, developed jointly in Dresden and Nijmegen, for reasoning (with a backend theorem prover) about classes in objectoriented languages. It will describe reasoning both about objectoriented specifications and about JAVA implementations, via examples. 1 Introduction One of the key aspects of objectorientation is that objects, as instances of a class, have a private state, which can only be accessed and modified via the operations (usually called attributes and methods) of the class of the object. It is precisely this aspect which forms the starting point of the coalgebraic analysis of classes and objects in an objectoriented setting, see [10,5]: a class is seen as a coalgebra, and an object of a class as an element of the state space of the coalgebra. More precisely, a coalgebra is an operation of the form c: X ! T (X), where X is the carrier set (or state sp...
From Bialgebraic Semantics to Congruence Formats
, 2005
"... A general and abstract framework to defining congruence formats for various process equivalences coalgebraic approach to process equivalence, based on a notion of test suite. The resulting technique is illustrated on the example of completed trace equivalence. Rather than providing formal proofs, th ..."
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Cited by 10 (4 self)
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A general and abstract framework to defining congruence formats for various process equivalences coalgebraic approach to process equivalence, based on a notion of test suite. The resulting technique is illustrated on the example of completed trace equivalence. Rather than providing formal proofs, the paper is guiding the reader through the process of deriving a congruence format in the test suite approach.
Coalgebras For Binary Methods: Properties Of Bisimulations And Invariants
, 2001
"... Coalgebras for endofunctors C > C can be used to model classes of objectoriented languages. However, binary methods do not fit directly into this approach. This paper proposes an extension of the coalgebraic framework, namely the use of extended polynomial functors C^op x C > C . This extension ..."
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Cited by 9 (3 self)
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Coalgebras for endofunctors C > C can be used to model classes of objectoriented languages. However, binary methods do not fit directly into this approach. This paper proposes an extension of the coalgebraic framework, namely the use of extended polynomial functors C^op x C > C . This extension allows the incorporation of binary methods into coalgebraic class specifications. The paper also discusses how to define bisimulation and invariants for coalgebras of extended polynomial functors and proves many standard results. 1991 Mathematics Subject Classification. 03E20, 03G30, 68Q55, 68Q65.
Coalgebraic Theories of Sequences in PVS
, 1998
"... This paper explains the setting of an extensive formalisation of the theory of sequences (finite and infinite lists of elements of some data type) in the Prototype Verification System pvs. This formalisation is based on the characterisation of sequences as a final coalgebra, which is used as an axi ..."
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Cited by 8 (2 self)
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This paper explains the setting of an extensive formalisation of the theory of sequences (finite and infinite lists of elements of some data type) in the Prototype Verification System pvs. This formalisation is based on the characterisation of sequences as a final coalgebra, which is used as an axiom. The resulting theories comprise standard operations on sequences like composition (or concatenation), filtering, flattening, and their properties. They also involve the prefix ordering and proofs that sequences form an algebraic complete partial order. The finality axiom gives rise to various reasoning principles, like bisimulation, simulation, invariance, and induction for admissible predicates. Most of the proofs of equality statements are based on bisimulations, and most of the proofs of prefix order statements use simulations. Some significant aspects of these theories are described in detail. This coalgebraic formalisation of sequences is presented as a concrete example that shows t...
The least fibred lifting and the expressivity of coalgebraic modal logic
 In Proc. CALCO 2005, volume 3629 of LNCS
, 2005
"... and relationpreserving functions. In this paper, the least (fibrewise) of such liftings, L(B), is characterized for essentially any B. The lifting has all the useful properties of the relation lifting due to Jacobs, without the usual assumption of weak pullback preservation; if B preserves weak pu ..."
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Cited by 8 (1 self)
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and relationpreserving functions. In this paper, the least (fibrewise) of such liftings, L(B), is characterized for essentially any B. The lifting has all the useful properties of the relation lifting due to Jacobs, without the usual assumption of weak pullback preservation; if B preserves weak pullbacks, the two liftings coincide. Equivalence relations can be viewed as Boolean algebras of subsets (predicates, tests). This correspondence relates L(B) to the least test suite lifting T (B), which is defined in the spirit of predicate lifting as used in coalgebraic modal logic. Properties of T (B) translate to a general expressivity result for a modal logic for Bcoalgebras. In the resulting logic, modal operators of any arity can appear. 1