Brouwer, Luitzen Egbertus Jan[brower]
Mathematician, born in Overschie, The Netherlands. He studied at Amsterdam University at the age of 16, where he was professor (1912--51). He founded the intuitionist or constructivist school of mathematical logic, which does not accept the law of the excluded middle, and in which the existence of a mathematical object can only be proved by giving an explicit method for its construction. He also made fundamental advances in topology, proving the invariance of dimension, and the fixed point theorem named after him.