Knit Products of Some Groups and Their Applications

  • Firat Ateş

    Balikesir University, Turkey
  • A. Sinan Çevik

    Selçuk University, Konya, Turkey


Let be a group with subgroups and (not necessarily normal) such that and . Then is isomorphic to the knit product, that is, the “two-sided semidirect product” of by . We note that knit products coincide with Zappa-Szep products (see [18]).

In this paper, as an application of [2, Lemma 3.16], we first define a presentation for the knit product where and are finite cyclic subgroups. Then we give an example of this presentation by considering the (extended) Hecke groups. After that, by defining the Schur multiplier of , we present sufficient conditions for the presentation of to be efficient. In the final part of this paper, by examining the knit product of a free group of rank by an infinite cyclic group, we give necessary and sufficient conditions for this special knit product to be subgroup separable.

Cite this article

Firat Ateş, A. Sinan Çevik, Knit Products of Some Groups and Their Applications. Rend. Sem. Mat. Univ. Padova 121 (2009), pp. 1–11

DOI 10.4171/RSMUP/121-1