Bass–Serre theory
= Bass–Serre theory
{wiki=Bass–Serre_theory}
Bass–Serre theory is a branch of algebraic topology that studies the relationships between groups and their actions on trees (in a combinatorial sense). Developed by mathematicians Hyman Bass and Jean-Pierre Serre in the 1960s, the theory provides a framework for understanding certain types of groups, particularly finitely generated groups that can be decomposed in terms of simpler pieces.