Thom 1954: oriented-cobordism ring Ω*; computed via Thom-Pontryagin construction. Manifolds modulo bordism. Smooth / symplectic / spin / framed variants. Foundation of differential-topology.
Thom 1954: oriented-cobordism ring Ω*; computed via Thom-Pontryagin construction. Manifolds modulo bordism. Smooth / symplectic / spin / framed variants. Foundation of differential-topology.