Atiyah-Hirzebruch 1959-61: K^0(X) = Grothendieck-group of vector-bundles on X. Bott-periodicity K^n(pt) period 2 (complex) / 8 (real). Foundation of index theory + algebraic-K-theory.
Atiyah-Hirzebruch 1959-61: K^0(X) = Grothendieck-group of vector-bundles on X. Bott-periodicity K^n(pt) period 2 (complex) / 8 (real). Foundation of index theory + algebraic-K-theory.