We show that fixed membership testing for many interesting subclasses of multi-pushdown machines is no harder than for pushdowns with single stack. The models we consider are MVPA, OVPA and MPDA, which have all been defined and studied in the past. Multi-stack pushdown automata, MPDA, have ordered stacks with pop access restricted to the stack-top of the first non-empty stack. The membership fo...

In this paper we examine a new class of languages defined by Alur and Madhusudan called visibly pushdown languages and use them to study the word problem for finitely generated groups.

We first give an improved lower bound for the deterministic onlinesimulation of tapes or pushdown stores by queues. Then we inspect some proofs in a classical work on queue machines in the area of Formal Languages and outline why a main argument in the proofs is incomplete.

We first consider infinite two-player games on pushdown graphs. In previous work, Cachat, Duparc and Thomas [4] have presented a winning decidable condition that is Σ3-complete in the Borel hierarchy. This was the first example of a decidable winning condition of such Borel complexity. We extend this result by giving a family of decidable winning conditions of arbitrary finite Borel complexity....

We prove that the class of the classifying stack BPGLn is the multiplicative inverse of the class of the projective linear group PGLn in the Grothendieck ring of stacks K0(Stackk) for n = 2 and n = 3 under mild conditions on the base field k. In particular, although it is known that the multiplicativity relation {T} = {S} · {PGLn} does not hold for all PGLntorsors T → S, it holds for the univer...

Electrochemical impedance spectroscopy (EIS) is a suitable and powerful diagnostic testing method for fuel cells (FCs) since it is non-destructive and provides useful information about FC performance and its components. In this study, for the first time, a 500W cascade type 4 cells stack with integrated humidifier, water separator and internal manifolds was designed, fabricated and tested. The ...