Date of this Version
Rajeev Alur, Viraj Kumar, P. Madhusudan, and Mahesh Viswanathan, "Congruences for Visibly Pushdown Languages", Lecture Notes in Computer Science: Automata, Languages and Programming 3580, 1102-1114. July 2005. http://dx.doi.org/10.1007/11523468_89
We study congruences on words in order to characterize the class of visibly pushdown languages (VPL), a subclass of context-free languages. For any language L, we define a natural congruence on words that resembles the syntactic congruence for regular languages such that this congruence is of finite index if, and only if, L is a VPL. We then study the problem of finding canonical minimal deterministic automata for VPLs. Though VPLs in general do not have unique minimal automata, we consider a subclass of VPAs called k-module single-entry VPAs that correspond to programs with recursive procedures without input parameters, and show that the class of well-matched VPLs do indeed have unique minimal k-module single-entry automata. We also give a polynomial time algorithm that minimizes such k-module single-entry VPAs.
CPS Formal Methods, CPS Theory
Lecture Notes in Computer Science: Automata, Languages and Programming
The original publication is available at www.springerlink.com
Date Posted: 02 November 2005