121 research outputs found
Small NFAs from Regular Expressions: Some Experimental Results
Regular expressions (res), because of their succinctness and clear syntax,
are the common choice to represent regular languages. However, efficient
pattern matching or word recognition depend on the size of the equivalent
nondeterministic finite automata (NFA). We present the implementation of
several algorithms for constructing small epsilon-free NFAss from res within
the FAdo system, and a comparison of regular expression measures and NFA sizes
based on experimental results obtained from uniform random generated res. For
this analysis, nonredundant res and reduced res in star normal form were
considered.Comment: Proceedings of 6th Conference on Computability in Europe (CIE 2010),
pages 194-203, Ponta Delgada, Azores, Portugal, June/July 201
Deciding KAT and Hoare Logic with Derivatives
Kleene algebra with tests (KAT) is an equational system for program
verification, which is the combination of Boolean algebra (BA) and Kleene
algebra (KA), the algebra of regular expressions. In particular, KAT subsumes
the propositional fragment of Hoare logic (PHL) which is a formal system for
the specification and verification of programs, and that is currently the base
of most tools for checking program correctness. Both the equational theory of
KAT and the encoding of PHL in KAT are known to be decidable. In this paper we
present a new decision procedure for the equivalence of two KAT expressions
based on the notion of partial derivatives. We also introduce the notion of
derivative modulo particular sets of equations. With this we extend the
previous procedure for deciding PHL. Some experimental results are also
presented.Comment: In Proceedings GandALF 2012, arXiv:1210.202
Automata Serialization for Manipulation and Drawing
GUItar is a GPL-licensed, cross-platform, graphical user interface for automata drawing and manipulation, written in C++ and Qt5. This tool offers support for styling, automatic layouts, several format exports and interface with any foreign finite automata manipulation library that can parse the serialized XML or JSON produced. In this paper we describe a new redesign of the GUItar framework and specially the method used to interface GUItar with automata manipulation libraries
Partial Derivative Automaton for Regular Expressions with Shuffle
We generalize the partial derivative automaton to regular expressions with
shuffle and study its size in the worst and in the average case. The number of
states of the partial derivative automata is in the worst case at most 2^m,
where m is the number of letters in the expression, while asymptotically and on
average it is no more than (4/3)^m
State Elimination Ordering Strategies: Some Experimental Results
Recently, the problem of obtaining a short regular expression equivalent to a
given finite automaton has been intensively investigated. Algorithms for
converting finite automata to regular expressions have an exponential blow-up
in the worst-case. To overcome this, simple heuristic methods have been
proposed.
In this paper we analyse some of the heuristics presented in the literature
and propose new ones. We also present some experimental comparative results
based on uniform random generated deterministic finite automata.Comment: In Proceedings DCFS 2010, arXiv:1008.127
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