Wolfgang Thomas

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This paper is a survey on logical aspects of nite automata. Central points are the connection between nite automata and monadic second-order logic, the Ehrenfeucht-Fra ss e technique in the context of formal language theory, nite automata on !-words and their determinization, and a self-contained proof of the \Rabin Tree Theorem". Sections 5 and 6 contain(More)
Completeness and Weak Completeness Under Polynomial-Size Circuits p. 26 Communication Complexity of Key Agreement on Small Ranges p. 38 Pseudorandom Generators and the Frequency of Simplicity p. 50 Classes of Bounded Counting Type and their Inclusion Relations p. 60 Lower Bounds for Depth-Three Circuits With Equals and Mod-Gates p. 71 On Realizing Iterated(More)
In this paper we study the expressive power of the full branching time logic CTL* (of Clarke, Emerson, Halpern and Sistla), by comparing it with fragments of monadic second-order lo~ic over the binary tree. We show that over binary tree models the system CTLhas the same expressive power as monadic second-order logic in which set quantification is restricted(More)
We present a method to solve certain infinite games over finite state spaces and apply this for the automatic synthesis of finitestate controllers. A lift-controller problem serves as an example for which the implementation of our algorithm has been tested. The specifications consist of safety conditions and so-called “request-response-conditions” (which(More)
We investigate bottom-up and top-down deterministic automata on unranked trees. We show that for an appropriate definition of bottom-up deterministic automata it is possible to minimize the number of states efficiently and to obtain a unique canonical representative of the accepted tree language. For top-down deterministic automata it is well known that(More)