Fixed points

Vector-field indices, Brouwer, Lefschetz, and Sperner.

The Poincaré-Hopf index theorem (1885-1927)

The Poincaré-Hopf index theorem (1885-1927)

Brouwer’s fixed-point theorem (1911)

Brouwer's fixed-point theorem (1911)

Lefschetz’s fixed-point theorem and Hopf’s trace formula (1926-1929)

Lefschetz's fixed-point theorem and Hopf's trace formula (1926-1929)

Sperner’s lemma (1928)

Sperner's lemma (1928)