Heinz Hopf
was born 123 years ago
19th November 1894

Heinz Hopf's work was in algebraic topology. He studied vector fields and extended Lefschetz's fixed point formula. He also studied homotopy classes and defined what is now known as the 'Hopf invariant'.

Find out more at:
http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Hopf.html