Over the last decades the theory of automata on infinite objects has been an important source of tools for the specification and the verification of computer programs. Trees are more suitable than words to model nondeterminism and concurrency. In the literature, there are several examples of acceptance conditions that have been proposed for automata on infinite words and then have been fruitful...

Innnite leaf alphabets provide a new approach to remove the connection between the sizes of the leaf alphabet and the set of states of a tree automaton. Unique minimal tree automata can be constructed for classes of tree automata; however, such a class cannot be nite.

Finite tree automata consist of a set of states and a set of transitions. Input trees are accepted if it is possible to label the tree with states such that the relationship between the state at every node and the state at its child nodes conforms to a transition. Thus, the transitions only define how a state must be labeled with respect to its children or vice versa. This work investigates how...

This article presents the basic theory of automata on infinite trees. We introduce the standard model of nondeterministic automata and the generalization to alternating automata. The central part of the theory considers the closure properties of tree languages definable by such automata, the equivalence of the different models, and their algorithmic properties. We show how these results are obt...

We present a disambiguation algorithm for weighted finite tree automata (FTA). This algorithm converts ambiguous FTA into equivalent non-ambiguous one where no two accepting paths labeled with the same tree exists. The notion of non-ambiguity is similar to that of determinism in the automata theory, but we show that disambiguation is applicable to the wider class of weighted automata than deter...

We investigate rational relations over trees. Our starting point is the definition of rational tree relations via rational expressions byRaoult (Bull. Belg.Math. Soc. 1997). We develop a new class of automata, called asynchronous tree automata, which recognize exactly these relations. The automata theoretic approach is convenient for the solution of algorithmic problems (like the emptiness prob...

We propose a notion of morphisms between tree automata based on game semantics. Morphisms are winning strategies on a synchronous restriction of the linear implication between acceptance games. This leads to split indexed categories, with substitution based on a suitable notion of synchronous tree function. By restricting to tree functions issued from maps on alphabets, this gives a fibration o...

Chaudhari S. R. ,Komejwar D. D. , On Fuzzy Pushdown Automata and their covering , International Journal of Computer Applications Vol. 46(8),2012 pp 27-33 Comon H. ,Dauchet M. ,Gilleron R. ,Jacquemard F. , Lugiez D. ,Loding C. ,Tison S. , and Tommasi M. , Tree Automata: techniques and apllications. (2007) Lee E. T. Fuzzy tree automata and syntactic pattern recognition, IEEE Trans Pattern Anal Ma...

Two examples of automata-theoretic models for the validation of xml documents against user-de ned schema are the stepwise unranked tree automaton (suta) and the parallel unranked tree automaton (puta). By adding a weight, taken from some semiring, to every transition we generalise these two qualitative automata models to quantitative models, thereby obtaining weighted stepwise unranked tree aut...

Every graph property expressible in monadic second-order (MSO) logic, possibly with quantifications over edges, can be checked in linear time on graphs of bounded tree-width, in particular by means of finite automata running on terms denoting tree-decompositions. However, implementing these automata is difficult because of their huge sizes. Fly-automata (FA) are deterministic automata that comp...