Pushdown automaton

About: Pushdown automaton is a research topic. Over the lifetime, 1868 publications have been published within this topic receiving 35399 citations.

Using domain information during the learning of a subsequential transducer

Abstract: The recently proposed OSTI algorithm allows for the identification of subsequential functions from input-output pairs. However, if the target is a partial function the convergence is not guaranteed. In this work, we extend the algorithm in order to allow for the identification of any partial subsequential function provided that either a negative sample or a description of the domain by means of a deterministic finite automaton is available.

A Simple Construction Method of a Reversible Finite Automaton out of Fredkin Gates, and Its Related Problem

Abstract: A reversible finite automaton (RFA) is a backward deterministic automaton, i.e., it can uniquely retrace its move sequence if the inverse sequence of its outputs is given. In this paper, we show a simple method to construct an RF A from Fredkin gates, which are reversible and bit-conserving logic gates, and unit wires (unit delays) . The resulting circuit obtained by this method is \"garbage-less\" in the sense that it has no inputs to which constants must be supplied nor outputs from which garbage signals are put out. We also show that a one-dimensional revers­ ible partitioned cellular automaton, which are known to be com­ putation universal, can be constructed from Fredkin gates and unit wires as a closed (thus garbage-less) infinite circuit.

C-SHORe: a collapsible approach to higher-order verification

Abstract: Higher-order recursion schemes (HORS) have recently received much attention as a useful abstraction of higher-order functional programs with a number of new verification techniques employing HORS model-checking as their centrepiece. This paper contributes to the ongoing quest for a truly scalable model-checker for HORS by offering a different, automata theoretic perspective. We introduce the first practical model-checking algorithm that acts on a generalisation of pushdown automata equi-expressive with HORS called collapsible pushdown systems (CPDS). At its core is a substantial modification of a recently studied saturation algorithm for CPDS. In particular it is able to use information gathered from an approximate forward reachability analysis to guide its backward search. Moreover, we introduce an algorithm that prunes the CPDS prior to model-checking and a method for extracting counter-examples in negative instances. We compare our tool with the state-of-the-art verification tools for HORS and obtain encouraging results. In contrast to some of the main competition tackling the same problem, our algorithm is fixed-parameter tractable, and we also offer significantly improved performance over the only previously published tool of which we are aware that also enjoys this property. The tool and additional material are available from http://cshore.cs.rhul.ac.uk.