The concatenation of trees can be defined either as a sequential or a parallel operation, and the corresponding iterated operation gives an extension of Kleene-star to tree languages. Since the sequential tree concatenation is not associative, we get two essentially different iterated sequential concatenation operations that we call the bottom-up star and top-down star operation, respectively. ...

Tree automata with one memory have been introduced in 2001. They generalize both pushdown (word) automata and the tree automata with constraints of equality between brothers of Bogaert and Tison. Though it has a decidable emptiness problem, the main weakness of this model is its lack of good closure properties. We propose a generalization of the visibly pushdown automata of Alur and Madhusudan ...

We introduce timed alternating tree automata as a natural extension of timed automata for the purpose of solving the model checking problem for timed computation tree logic (TCTL) following the automata-theoretic approach. This settles a problem posed by Hen-zinger, Kupferman, and Vardi. With their pioneering work in the late fties and early sixties, BBchi, Rabin, Trakhtenbrot and others demons...

A large fraction of an XML document typically consists of text data. The XPath query language allows text search via the equal, contains, and starts-with predicates. Such predicates can efficiently be implemented using a compressed self-index of the document’s text nodes. Most queries, however, contain some parts of querying the text of the document, plus some parts of querying the tree structu...

Cellular automata (CA) consist of an array of identical cells, each of which may take one of a finite number of possible states. The entire array evolves in discrete time steps by iterating a global evolution G. Further, this global evolution G is required to be shift-invariant (it acts the same everywhere) and causal (information cannot be transmitted faster than some fixed number of cells per...

Available online 26 October 2013 Segregationmodels often focus onprivate racial preference but overlook the institutional context. This paper represents an effort to move beyond the preference centricity. In this paper, an ideal Pigovian regulatory intervention is emulated and added into Schelling’s (1971) classic spatial proximity model of racial segregation, with an aim to preserve collective...

2 Automata over forests 4 2.1 Forest automata . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 Bottom-up deterministic forest automata . . . . . . . . . . 5 2.3 Minimization of BUDFA . . . . . . . . . . . . . . . . . . . 8 2.4 BUNFA and determinization . . . . . . . . . . . . . . . . . 14 2.5 Computing the syntactic forest algebra of a language . . . 16 2.6 Logical characterization . . . ....

This paper focuses on the realizability problem of a framework for modeling and specifying the global behaviors of reactive electronic services (e-services). In this framework, Web accessible programs (peers) communicate by asynchronous message passing, and a virtual global watcher silently listens to the network. The global behavior is characterized by a “conversation”, which is the infinite s...

Tree automata with one memory have been introduced in 2001. They generalize both pushdown (word) automata and the tree automata with constraints of equality between brothers of Bogaert and Tison. Though it has a decidable emptiness problem, the main weakness of this model is its lack of good closure properties. We propose a generalization of the visibly pushdown automata of Alur and Madhusudan ...