A basic property which distributed communicating systems have to fulfill is deadlock-freedom. For systems consisting of the parallel composition of subsystems it is complex to check deadlock-freedom because the global state space of the composition has to be investigated. This paper presents an approach by which the absence of deadlocks is preserved during the development. Small initial deadloc...

The phase of a single state is not an observable quantity. In particular, the phase commutes with the observables which define the system. Nevertheless the change of states is generally accompanied by a change of the phase that can be called phase transport. If a state w is changed in two different ways to become another state w’, the transport of the phases may yield different phases. Then the...

In this paper, we write down the separable Werner state in a two-qubit system as a convex combination of product states explicitly. The Werner state in a two-qubit system has a single real parameter and varies from inseparable state to separable state according to the value of its parameter. The convex combination of product states gives a hidden variable model to the separable Werner state.

is stable. For infinite-dimensional systems the situation is more complicated. Although the eigenvalues still possess the same property as in the finite dimensional situation, they don’t longer rule the stability. Since many years it is an open question whether the stability of (1.1) and (1.2) are equivalent. For Banach spaces it is not hard to find a counter example, and so we concentrate on t...

While hidden class models of various types arise in many statistical applications, it is often difficult to establish the identifiability of their parameters. Focusing on models in which there is some structure of independence of some of the observed variables conditioned on hidden ones, we demonstrate a general approach for establishing identifiability utilizing algebraic arguments. A theorem ...

Ordered Binary Decision Diagrams (BDDs) are frequently used in logic synthesis. In this paper a new exact BDD minimization algorithm is presented, which is based on state space search. In contrast to all previous approaches, in which variables are moved through the BDD when exploring the state space, the new method makes use of a new technique to expand states to its successor states without ex...

State space-based simulation method of general stochastic continuous-time models suffers from its sensitivity to state space-explosion. In this paper, we address this problem by the introduction of variable time steps for the proxel-based simulation method. We show how the complexity of the simulation is reduced by expressing rare event probability using fewer computational units. It is shown b...

In this paper we develop a priori error analysis for Galerkin finite element discretizations of optimal control problems governed by linear parabolic equations. The space discretization of the state variable is done using usual conforming finite elements, whereas the time discretization is based on discontinuous Galerkin methods. For different types of control discretizations we provide error e...