Nielsen–Schreier theorem

ID: nielsen-schreier-theorem

The Nielsen–Schreier theorem is a result in group theory that provides a characterization of free groups in terms of their subgroups. The theorem states that every subgroup of a free group is free. More specifically, if \( F \) is a free group, then any subgroup \( H \) of \( F \) is itself a free group, possibly on a different set of generators.

New to topics? Read the docs here!