Modal specifications are classic, convenient, and expressive mathematical objects to represent interfaces of component-based systems. However, time is a crucial aspect of systems for practical applications, e.g. in the area of embedded systems. And yet, only few results exist on the design of timed component-based systems. In this paper, we propose a timed extension of modal specifications, tog...

ion refinement techniques in probabilistic model checking are prominent approaches to the verification of very large or infinite-state probabilistic concurrent systems. At the core of the refinement step lies the implicit or explicit analysis of a counterexample. This paper proposes an abstraction refinement approach for the probabilistic computation tree logic (PCTL), which is based on increme...

We formalize a unified framework for verified decision procedures for regular expression equivalence. Five recently published formalizations of such decision procedures (three based on derivatives, two on marked regular expressions) can be obtained as instances of the framework. We discover that the two approaches based on marked regular expressions, which were previously thought to be the same...

Confluence in abstract parallel category systems is established for net class-rewriting in iterative closed multilevel quotient graph structures with uncountable node arities by multi-dimensional transducer operations in topological metrics defined by alphabetically abstracting net block homomorphism. We obtain minimum prerequisites for the comprehensive connector pairs in a multitude dimension...

We formulate a sound and complete assume-guarantee framework for reasoning compositionally about components modelled as a variant of interface automata. The specification of a component, which expresses both safety and progress properties of input and output interactions with the environment, is characterised by finite traces. The framework supports dynamic reasoning about components and specif...

The paper presents a further step within a comprehensive program of “Dualizing Universal Algebra” [4, 7, 10, 11, 12]. We analyze the construction of subalgebras generated by a given subset (of generators) of the carrier of an algebra and reformulate it in a systematic categorical way. Dualizing the new categorical description, we obtain then the construction of quotient coalgebras “cogenerated”...

Many different deletion operations are investigated applied to languages accepted by one-way and two-way deterministic reversal-bounded multicounter machines as well as finite automata. Operations studied include the prefix, suffix, infix and outfix operations, as well as left and right quotient with languages from different families. It is often expected that language families defined from det...

the concept of right (left) quotient (or residual) of an ideal η by anideal ν of an l-subring μ of a ring r is introduced. the right (left) quotients areshown to be ideals of μ . it is proved that the right quotient [η :r ν ] of an idealη by an ideal ν of an l-subring μ is the largest ideal of μ such that[η :r ν ]ν ⊆ η . most of the results pertaining to the notion of quotients(or residual) of ...

Finite-state automata are a central computational model in computer science, with numerous and diverse applications. In one such application, viz. model-checking, automata over infinite words play a central rôle. In this thesis, we concentrate on Büchi automata (BA), which are arguably the simplest finite-state model recognizing languages of infinite words. Two algorithmic problems are paramoun...