On recognition of languages of arbitrary words by finite semigroups

Based on methods of nonstandard analysis we elaborate in this paper a new approach to the theory of infinite products in finite semigroups. The main theorems of the paper show that infinite products of elements of standard sequences in finite semigroups can be viewed as a two-sided algebraic counterpart of finite products of a special kind. Using these results we construct a universal functor of the category of finite semigroups to the category of finite four-sorted algebras of a special kind and introduce a notion of a language of arbitrary words recognized by finite semigroups. Applications of these methods to the theory of recognizable languages on finite semigroups are considered.