The concept of a synchronized extension system (SE-system, for short) has been introduced in by Ţiplea et al. [Acta Inform., to appear] as a 4-tuple G = (V ,L1,L2, S), where V is an alphabet and L1, L2 and S are languages over V . Such systems generate languages extending L1 by L2 to the left or to the right, and synchronizing on words in S. Ţiplea et al. showed that the language of type r− gen...

We introduce the notion of twisted jets. For a DeligneMumford stack X of finite type over C, a twisted ∞-jet on X is a representable morphism D → X such that D is a smooth DeligneMumford stack with the coarse moduli space SpecC[[t]]. We study the motivic measure on the space of the twisted ∞-jets on a smooth Deligne-Mumford stack. As an application, we prove that two birational minimal models w...

A circular Nim game is a two player impartial combinatorial game consisting of n stacks of tokens placed in a circle. A move consists of choosing k consecutive stacks, and taking at least one token from one or more of the k stacks. The last player able to make a move wins. We prove results on the structure of the losing positions for small n and k and pose some open questions for further invest...

Walukiewicz gave in 1996 a solution for parity games on pushdown graphs: he proved the existence of pushdown strategies and determined the winner with an EXPTIME procedure. We give a new presentation and a new algorithmic proof of these results, obtain a uniform solution for parity games (independent of their initial configuration), and extend the results to prefix-recognizable graphs. The winn...

ion Refinement for Pushdown Systems

Recent studies have demonstrated that measured wide-area network traac such as Internet traac exhibits locally complex irregularities, consistent with multifractal behavior. It has also been shown that the observed multifractal structure becomes most apparent when analyzing measured network traac at a particular layer in the well-deened protocol hierarchy that characterizes modern data networks...

The purpose of this study was to evaluate the effect of pallet type, tie-sheet and stack configuration on compression strength of a palletized load of boxes. Four boxes made from similar board grade and different dimensions were selected for this study. The col­ umn stack configuration which represented the control was compared with the 3 stack configurations either on a CHEP® or GMA pallet. Th...

A common type of memory error in the Linux kernel is using uninitialized variables (uninitialized use). Uninitialized uses not only cause undefined behaviors but also impose a severe security risk if an attacker takes control of the uninitialized variables. However, reliably exploiting uninitialized uses on the kernel stack has been considered infeasible until now since the code executed prior ...

Conventional approaches to compiler correctness, type safety and type preservation have focused on off-line proofs, either on paper or formalised with a machine, of existing compilation schemes with respect to a reference operational semantics. This pearl shows how the use of dependent types in programming, illustrated here in Epigram, allows us not only to build-in these properties, but to wri...

The emergence of stacks as a hardware device in stack machines implies the recognition of the importance of using stacks in different computer applications and the need to make use of them in others. This paper uses stacks to solve the sorting problem. Two stack-based sorting algorithms are introduced. The first is based upon sorting by the insertion technique, whereas the second is based upon ...