Abstract
If a finite group G has a presentation with d generators and r relations, it is well known that r-d is at least the rank of the Schur multiplier of G; a presentation is called efficient if equality holds. There is an analogous definition for proficient profinite presentations. We show that many perfect groups have proficient presentations. Moreover, we prove that infinitely many alternating groups, symmetric groups and their double covers have proficient presentations.
Original language | English |
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Pages (from-to) | 169-184 |
Number of pages | 16 |
Journal | Journal of Algebra |
Volume | 326 |
Issue number | 1 |
DOIs | |
State | Published - 15 Jan 2011 |
Keywords
- Cohomology
- Efficient groups
- Presentations of finite groups
- Proficient groups
- Profinite groups