Determining Subgroups of a Given Finite Index in a Finitely Presented Group
- 1 August 1974
- journal article
- Published by Canadian Mathematical Society in Canadian Journal of Mathematics
- Vol. 26 (4) , 769-782
- https://doi.org/10.4153/cjm-1974-072-0
Abstract
The use of computers to investigate groups has mainly been restricted to finite groups. In this work, a method is given for finding all subgroups of finite index in a given group, which works equally well for finite and for infinite groups. The basic object of study is the finite set of cosets. §2 reviews briefly the representation of a subgroup by permutations of its cosets, introduces the concept of normal coset numbering, due independently to M. Schaps and C. Sims, and describes a version of the Todd-Coxeter algorithm. §3 contains a version due to A. Dietze of a process which was communicated to J. Neubuser by C. Sims, as well as a proof that the process solves the problem stated in the title. A second such process, developed independently by M. Schaps, is described in §4. §5 gives a method for classifying the subgroups by conjugacy, and §6, a suggestion for generalization of the methods to permutation and matrix groups.Keywords
This publication has 3 references indexed in Scilit:
- An Algorithmic Solution for a Word Problem in Group TheoryCanadian Journal of Mathematics, 1964
- Programmierung der Restklassenabzählung einer Gruppe nach UntergruppenNumerische Mathematik, 1961
- A practical method for enumerating cosets of a finite abstract groupProceedings of the Edinburgh Mathematical Society, 1936