Now showing items 1-3 of 3

  • Cancellative and Malcev presentations for finite Rees index subsemigroups and extensions 

    Cain, Alan James; Robertson, Edmund Frederick; Ruskuc, Nik (2008-02) - Journal article
    It is known that, for semigroups, the property of admitting a finite presentation is preserved on passing to subsemigroups and extensions of finite Rees index. The present paper shows that the same holds true for Malcev, ...
  • Generators and relations for subsemigroups via boundaries in Cayley graphs 

    Gray, R; Ruskuc, Nik (2011-11) - Journal article
    Given a finitely generated semigroup S and subsemigroup T of S we define the notion of the boundary of T in S which, intuitively, describes the position of T inside the left and right Cayley graphs of S. We prove that if ...
  • Properties of the subsemigroups of the bicyclic monoid 

    Descalco, L.; Ruskuc, Nik (2008-06) - Journal article
    In this paper we study some properties of the subsemigroups of the bicyclic monoid B, by using a recent description of its subsemigroups. We start by giving necessary and sufficient conditions for a subsemigroup to be ...