Marek A. Bednarczyk

Learn More
Given a finite state system with partial observers and for each observer, a regular set of trajectories which we call a secret, we consider the question whether the observers can ever find out that a trajectory of the system belongs to some secret. We search for a regular control on the system, enforcing the specified secrets on the observers, even though(More)
The paper generalizes the notion of a congruence on a category and pursues some of its applications. In particular, generalized congruences are used to provide a concrete construction of coequalizers in Cat. Extremal, regular and various other classes of epimorphic functors are characterized and interrelated .
Petri hypernets, a novel framework for modeling mobile agents based on nets-within-nets paradigm is presented. Hypernets employ a local and finitary character of interactions between agents, and provide means for a modular and hierarchical description. They are capable of modelling mobile agents tfrahat can dynamically change their hierarchy, and can(More)
Two, seemingly different modular techniques for concurrent system development are investigated from a categorical perspective. A novel approach is presented in which they turn out to be merely special instances of pullback, a general categorical limit construction. Interestingly , the approach is based on truly concurrent semantics of systems. A transition(More)
We present a model checking algorithm for alternating-time temporal logic (ATL) with imperfect information and imperfect recall. This variant of ATL is arguably most appropriate when it comes to modeling and specication of multi-agent systems. The related variant of model checking is known to be theoretically hard (∆ P 2-to PSPACE-complete, depending on the(More)
The paper introduces the notion of concurrent realization of reactive systems. A framework is also presented in which labelled safe Petri nets as concurrent realizations of concrete asynchronous systems are constructed. The construction is uniform in the sense that it extends to a realization of an arbitrary diagram. We discuss applicability of the(More)
The problem of finding a (functorial) concurrent realization of a reactive system by means of a labelled safe Petri net is studied. Firstly, a (functorial) construction is described that leads from the category of concrete asynchronous systems introduced by Morin to the category of labelled safe Petri nets. Then, the general problem is discussed. It is(More)
Petri hypernets offer a formalism suitable for modelling dynamic agents operating in hierarchically structured environments. They can manipulate other agents as tokens, and be manipulated as tokens by other agents at the same time. The hierarchical structure of hypernets is not static in contrast to other models of mobility based on Petri nets. Agents can(More)