We propose a coalgebraic definition of weak bisimulation for a class of coalgebras obtained from bifunctors in~$SetCat$. Weak bisimilarity for a system is obtained as strong bisimilarity of a transformed system. The transformation consists of two steps: First, the behaviour on actions is expanded to behaviour on finite words …
read moreAutomata, Bitstream functions, and Circuits
We present a general and constructive method that for a well-behaved function on bitstreams: f: (2^omega)^n --> (2^omega)^m constructs a digital circuit (with n inputs and m outputs) that implements f. More precisely, the method will produce for such f a Mealy automaton that implements f. From …
read moreCompositionality in Logics for Coalgebras
The coalgebraic approach to modelling state-based systems allows system combinations to be modelled at the level of coalgebraic signatures using operations such as functor composition, product or coproduct. We show that this compositionality at the level of signatures can be lifted to a logical level, thereby allowing the derivation of …
read moreWhat semantics fits with my aspects?
In this talk, we review the available semantics for aspect-oriented programming (AOP), and we connect this theme of recent research to pre-AOP age. Most AOP semantics are operational or compiler-oriented in style, and they focus on idioms of AspectJ, which is the trend-setting, Java-based AOP language. A typical AOP semantics …
read moreBack To The Future: A Family of Algorithms for Termination Detection in Distributed Systems (Part 1)
A classical problem in distributed systems is detecting the termination of a distributed computation. Distributed Termination Detection (DTD) has been extensively studied in the past twenty years and it is known to be a difficult problem to solve efficiently, because it involves properties of the global state of a distributed …
read moreXML+RML
XML is a "syntax franca" in the computer industry, like English and mathematics are a "lingua franca" in publications in the field of computing science. Theories, formulas and logic rules can be stated in a suitable XML vocabulary. But such an XML encoding is only for the syntax, it is …
read moreAutomata and Fixed Point Logics for Coalgebras (part 2)
There is a long tradition in theoretical computer science connecting logic and automata theory. As a paradigmatic example we mention the link between the modal mu-calculus and parity automata on graphs. Much of this work has a strong coalgebraic flavour, but to our knowledge this perspective has never been made …
read moreIn the Name of the Role (sequel)
This presentation introduces a formalism for the specification of generic behavioral interfaces, so called roles. The main characteristic feature of this formalism is the dynamic creation of processes that act in the name of their roles. I will present a compositional trace semantics of roles which is fully abstract with …
read moreAutomata and Fixed Point Logics for Coalgebras
There is a long tradition in theoretical computer science connecting logic and automata theory. As a paradigmatic example we mention the link between the modal mu-calculus and parity automata on graphs. Much of this work has a strong coalgebraic flavour, but to our knowledge this perspective has never been made …
read moreIn the Name of the Role
This presentation introduces a formalism for the specification of generic behavioral interfaces, so called roles. The main characteristic feature of this formalism is the dynamic creation of processes that act in the name of their roles. I will present a compositional trace semantics of roles which is fully abstract with …
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