Nielsen–Schreier theorem
= Nielsen–Schreier theorem
{c}
{wiki}
Every <subgroup> of a <free group> is itself a <free group>. The theorem follows by representing the subgroup by a connected <covering graph> of a rose and choosing a maximal subtree.
= Nielsen–Schreier theorem
{c}
{wiki}
Every <subgroup> of a <free group> is itself a <free group>. The theorem follows by representing the subgroup by a connected <covering graph> of a rose and choosing a maximal subtree.