FenchelNielsenZomorrodian.Discrete.GroupTheory

2 sections | 2 files | 8 declarations

This module develops Fenchel--Nielsen--Zomorrodian presentation reductions, period relations, reindexings, and quotient maps.

Basic

1 files | 4 declarations | 2 Theorem | 2 Definition

A group is torsion-free when every element of finite order is trivial.

1 files | 4 declarations | 4 Theorem

This module records elementary facts about derived series, surjective homomorphisms, commutative groups, and universe lifts.