Visibly Pushdown Transducers (VPT) form a subclass of pushdown transducers. In this paper, we investigate the extension of VPT with visibly pushdown look-ahead (VPTla). Their transitions are guarded by visibly pushdown automata that can check whether the well-nested subword starting at the current position belongs to the language they define. First, we show that VPTla are not more expressive th...

machine that behaves as a pushdown automaton. In practical terms, Proposition 5.1 states that the history mechanism and the back button introduce a new class of hypertext systems, whose navigation space, i.e. hyperconnectivity, can only be provided by a more powerful class of hypertext systems. It should be observed that the hyperconnectivity generated by links is in fact specified by the autho...

In an exercise in the first volume of his famous series of books, Knuth considered sorting permutations by passing them through a stack. Many variations of this exercise have since been considered, including allowing multiple passes through the stack and using different data structures. We are concerned with a variation using pop-stacks that was introduced byAvis andNewborn in 1981. Let Pk(x) b...

This paper presents a toolset for model checking x86 executables. The members of the toolset are CodeSurfer/x86, WPDS++, and the Path Inspector. CodeSurfer/x86 is used to extract a model from an executable in the form of a weighted pushdown system. WPDS++ is a library for answering generalized reachability queries on weighted pushdown systems. The Path Inspector is a software model checker buil...

DEFINITION. A de termin i s t i c l inear bounded a u t o m a t o n (DLBA) is a sixtuple (Q, q0, V, # 1 , # 2 , J ) where: Q is a finite set of states q o , q l .... ; q o E Q is the initial state; V is a finite vocabulary; # 1 , #2 6 V are left and right endmarkers, respectively; and J is a finite set of instructions. T h e automaton consists of two pushdown lists, called L and R, and a finite...

We continue the investigation of finite-duration variants of infinite-duration games by extending known results for games played on finite graphs to those played on infinite ones. In particular, we establish an equivalence between pushdown parity games and a finite-duration variant. This allows to determine the winner of a pushdown parity game by solving a reachability game on a finite tree.

In this paper we study the stability of a recently proposed flow control algorithm for fair bandwidth sharing of a bottleneck access link. We present necessary conditions for stability for an arbitrary set of propagation delays. The analysis presented also facilitates proper configuration of the algorithms parameters.

Sun Microsystems Laboratories 1.1 Designing Concurrent Data Structures . . . . . . . . . . . . . 1-1 Performance • Blocking Techniques • Nonblocking Techniques • Complexity Measures • Correctness • Verification Techniques • Tools of the Trade 1.2 Shared Counters and Fetch-and-φ Structures . . . . . 1-12 1.3 Stacks and Queues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

We show that graphs generated by collapsible pushdown systems of level 2 are tree-automatic. Even if we allow ε-contractions and reachability predicates (with regular constraints) for pairs of configurations, the structures remain tree-automatic whence their first-order logic theories are decidable. As a corollary we obtain the tree-automaticity of the second level of the Caucal-hierarchy.