Principal G-bundle P → M with connection 1-form A; curvature F = dA + A∧A. Yang-Mills action ∫|F|² extremised by Maxwell (abelian) or Yang-Mills (non-abelian) equations. Foundation for standard model + Atiyah-Singer + Donaldson.
Principal G-bundle P → M with connection 1-form A; curvature F = dA + A∧A. Yang-Mills action ∫|F|² extremised by Maxwell (abelian) or Yang-Mills (non-abelian) equations. Foundation for standard model + Atiyah-Singer + Donaldson.