Quasi-identities of Finite Semigroups and Symbolic Dynamics

Relatively Inherently Nonfinitely Q-based Semigroups

We prove that every semigroup S whose quasivariety contains a 3-nilpotent semigroup or a semigroup of index more than 2 has no finite basis for its quasi-identities provided that one of the following properties holds: • S is finite; • S has a faithful representation by injective partial maps on a set; • S has a faithful representation by order preserving maps on a chain. As a corollary it is sh...

Symbolic dynamics

This chapter presents some of the links between automata theory and symbolic dynamics. The emphasis is on two particular points. The first one is the interplay between some particular classes of automata, such as local automata and results on embeddings of shifts of finite type. The second one is the connection between syntactic semigroups and the classification of sofic shifts up to conjugacy.

n–ary hyperstructures constructed from binary quasi–ordered semigroups

Based on works by Davvaz, Vougiouklis and Leoreanu-Fotea in the field of n–ary hyperstructures and binary relations we present a construction of n–ary hyperstructures from binary quasi-ordered semigroups. We not only construct the hyperstructures but also study their important elements such as identities, scalar identities or zeros. We also relate the results to earlier results obtained for a s...

Decidability and Tameness in the Theory of Finite Semigroups

Computational Complexity of Checking Identities in 0-simple Semigroups and Matrix Semigroups over Finite Fields

In this paper we analyze the so called word-problem for (finite) combinatorial 0-simple semigroups and matrix semigroups from the viewpoint of computational complexity.