Iannis Xenakis (Ιωάννης Ιάννης Ξενάκης) (May 29, 1922 – February 4, 2001) was a Greek composer, music theorist and architect. He is commonly recognized as one of the most important post-war avant-garde composers. Xenakis pioneered the use of mathematical models such as applications of set theory, varied use of stochastic processes, game theory, etc., in music, and was also an important influence on the development of electronic music.