Seminario Interdipartimentale
di Algoritmica
Monday,
April 21st, 2008, 12:00 noon
A survey of the Cerny
conjecture
Flavio
D'Alessandro, Department of Mathematics "Guido Castelnuovo", "Sapienza"
University of Rome
DI - Department of
Computer Science,
Via Salaria 113
Seminar Room, third floor
Abstract:
The
aim of this talk is to present an elementary survey on
a problem concerning synchronizing automata. A synchronizing automaton
is a model of computation, represented by a finite and oriented graph,
that satisfies a property called `synchronization'. Synchronizing
automata play a natural role in the solutionof several
very interesting problems of mathematics and theoretical
computer science. In the mid of 60s, Cerny proposed a conjecture on the
length of a minimal synchronizing word for a synchronizing automaton in
terms of the number of states. The validity of his conjecture is still
open, although it has been verified in many special
cases. Many of the nicest results concerning Cerny's conjecture are
algebraic in nature and essentialy use the theory of matrix
representations. In this talk, after a historical introduction of the
problem, we describe some relevant results as well as the
ideas underlying the techniques used to study the problem.