Now showing items 21-22 of 22

    • Presentations of inverse semigroups, their kernels and extensions 

      Carvalho, C.A.; Gray, R; Ruskuc, Nik (2011-06-01) - Journal article
      Let S be an inverse semigroup and let π:S→T be a surjective homomorphism with kernel K. We show how to obtain a presentation for K from a presentation for S, and vice versa. We then investigate the relationship between the ...
    • Simple extensions of combinatorial structures 

      Brignall, R; Ruskuc, Nik; Vatter, V (2011-07) - Journal article
      An interval in a combinatorial structure R is a set I of points which are related to every point in R \ I in the same way. A structure is simple if it has no proper intervals. Every combinatorial structure can be expressed ...