Nielsen-Schreier theorem

Every subgroupMathworldPlanetmathPlanetmath ( of a free groupMathworldPlanetmath is free.

This theorem is named after Jakob Nielsen, who in 1921 proved that every subgroup of a free group of finite rank ( is free, and Otto Schreier, who proved the full result in 1927.

Title Nielsen-Schreier theorem
Canonical name NielsenSchreierTheorem
Date of creation 2013-03-22 12:54:07
Last modified on 2013-03-22 12:54:07
Owner yark (2760)
Last modified by yark (2760)
Numerical id 9
Author yark (2760)
Entry type Theorem
Classification msc 20E05