A proof of Zhil'tsov's theorem on decidability of equational theory of epigroups

Epigroups are semigroups equipped with an additional unary operation called pseudoinversion. Each finite semigroup can be considered as epigroup. We prove the following theorem announced by Zhil'tsov in 2000: the equational theory of the class of all epigroups coincides with the equational theory of the class of all finite epigroups and is decidable. We show that the theory is not finitely based but provide a transparent infinite basis for it.Comment: 32 page

Dimension nn Representations of the Braid Group on nn Strings

In 1996 E. Formanek classified all the irreducible complex representations of $B_n$ of dimension at most $n-1,$ where $B_n$ is the Artin braid group on $n$ strings. In this paper we extend this classification to the representations of dimension $n,$ for $n\geq 9$. We prove that all such representations are equivalent to a tensor product of a one-dimensional representation and a specialization of a certain one-parameter family of $n-$dimensional representations, that was first discovered in 1996 by Tong, Yang, and Ma. We use our classification of irreducible complex representations of corank two, in the preprint math.GR/0003047.Comment: 6 page