The availability of weighted finite-state string automata toolkits made possible great advances in natural language processing. However, recent advances in syntax-based NLP model design are unsuitable for these toolkits. To combat this problem, we introduce a weighted finite-state tree automata toolkit, which incorporates recent developments in weighted tree automata theory and is useful for na...

The nonemptiness problem for nondeterministic automata on infinite words can be reduced to a sequence of reachability queries. The length of a shortest witness to the nonemptiness is then polynomial in the automaton. Nonemptiness algorithms for alternating automata translate them to nondeterministic automata. The exponential blow-up that the translation involves is justified by lower bounds for...

In this paper we introduce the concept of the quasi-product of tree automata. In a quasi-product the inputs of the component tree automata are operational symbols in which permutation and unification of variables are allowed. It is shown that in sets of tree automata which are homomorphically complete with respect to the quasiproduct the essentially unary operations play the basic role among al...

We address the concrete problem of implementing huge bottom-up term automata. Such automata arise from the verification of Monadic Second Order propositions on graphs of bounded tree-width or clique-width. This applies to graphs of bounded tree-width because bounded tree-width implies bounded clique-width. An automaton which has so many transitions that they cannot be stored in a transition tab...

We show how alternating automata provide decision procedures for the equality of inductively de3ned Boolean functions and present applications to reasoning about parameterized families of circuits. We use alternating word automata to formalize families of linearly structured circuits and alternating tree automata to formalize families of tree structured circuits. We provide complexity bounds fo...

We explore how formal methods and tools of the verification trade could be used for malware detection and analysis. In particular, we propose a new approach to learning and generalizing from observed malware behaviors based on tree automata inference. In particular, we develop an algorithm for inferring k-testable tree automata from system call dataflow dependency graphs and discuss the use of ...

Automata for unranked trees form a foundation for XML schemas, querying and pattern languages. We study the problem of efficiently minimizing such automata. First, we study unranked tree automata that are standard in database theory, assuming bottom-up determinism and that horizontal recursion is represented by deterministic finite automata. We show that minimal automata in that class are not u...

Unranked trees are a common concept in computer science. For instance (fully structured) XML-documents can be seen as unranked trees. With the help of unranked tree automata, one can investigate qualitative questions on XMLdocuments. To allow the study of quantitative aspects, Droste and Vogler (TOCS 2011) recently proposed and investigated bottom-up weighted unranked tree automata over semirin...

In this paper, we give a Nivat-like characterization for weighted alternating automata over commutative semirings (WAFA). To purpose prove that can be characterized as the concatenation of finite tree (WFTA) and specific class homomorphism. We show series recognized by is closed under inverses homomorphisms, but not homomorphisms. logical automata, which uses MSO logic trees. Finally investigat...

We present a novel, yet simple, technique for the speciication of context in struc-tured documents that we call caterpillar expressions. Although we are primarily applying this technique in the speciication of context-dependent style sheets for HTML, SGML and XML documents, it can also be used for query speciication for structured documents, as we shall demonstrate, and for the speciication of ...