I should explain that “Yang-Mills” theories are nonlinear generalizations of electrodynamics which can describe forces such as the weak and strong interactions.

— How Far Are We from the Quantum Theory of Gravity?, R. P. Woodard

Yang–Mills theory is a gauge theory based on the SU(N) group. It was formulated by Yang and Mills in 1954 in an effort to extend the original concept of gauge theory for an Abelian group, as was quantum electrodynamics, to the case of a nonabelian group with the intention to get an explanation for strong interactions.

— Wikipedia on Yang–Mills theory

2010.01.19 Tuesday ACHK