This paper describes a series of small universal Petri nets with inhibitor arcs. Four parameters of descriptional complexity are considered: the number of places, transitions, inhibitor arcs, and the maximal degree of a transition. A number of techniques for reducing the values of these parameters, with special attention on places, are presented: we describe strongly universal Petri nets with 3...

Pushdown systems (PDSs) model single-thread recursive programs, and well-structured transition systems (WSTSs), such as vector addition systems, are useful to represent non-recursive multi-thread programs. Combining these two ideas, our goal is to investigate wellstructured pushdown systems (WSPDSs), pushdown systems with wellquasi-ordered control states and stack alphabet. This paper focuses o...

In this paper we study supervisory control of discrete event systems using state variables for representation and speci cation. The motivation is two fold: rstly, a state variable representation allows a concise characterization of systems with in nitely many states, and secondly, state variable speci cation allows characterization of qualitative properties of general nondeterministic systems. ...

In this paper we study supervisory control of discrete event systems using state variables for representation and speciication. The motivation is two fold: rstly, a state variable representation allows a concise characterization of systems with innnitely many states, and secondly, state variable speciication allows characterization of qualitative properties of general nondeterministic systems. ...

The net analyte signal standard addition method was used for simultaneous spectrophotometric determination of sertraline and fluoxetine in pharmaceutical preparations. The method combines the advantages of the standard addition method with the net analyte signal concept to enable the extraction of information about an analyte from the spectra of multi-component mixtures. This method uses full s...

The differential between on-net and off-net prices, for example on mobile telephony networks, is hotly debated between telecoms operators and regulators. Small operators contend that their competitors’ high off-net prices are anticompetitive. We show that if the utility of receiving calls is taken into account, the equilibrium pricing structures will indeed depend on firms’ market shares. Large...

We consider a two-player infinite game with zero-reachability objectives played on a 2-dimensional vector addition system with states (VASS), the states of which are divided between the two players. Brázdil, Jančar, and Kučera (2010) have shown that for k > 0, deciding the winner in a game on k-dimensional VASS is in (k − 1)EXPTIME. In this paper, we show that, for k = 2, the problem is in P, a...

Isolating test cases from environment dependencies is often desirable, as it increases test reliability and reduces test execution time. However, code that calls non-virtual methods or consumes sealed classes is often impossible to test in isolation. Moles is a new lightweight framework which addresses this problem. For any .NET method, Moles allows test-code to provide alternative implementati...