Gödel or Goedel, Kurt[goedl]
Logician and mathematician, born in Brünn, Moravia (now Brno, Czech Republic). He studied and taught in Vienna, then emigrated to the USA in 1940 and joined the Institute of Advanced Study at Princeton. He became a US citizen in 1948. He stimulated significant work in mathematical logic and propounded one of the most important proofs in modern mathematics: Gödel's proof, published in 1931 with reference to Russells Principia mathemetica, showed that any formal logical system adequate for number theory must contain propositions not provable in that system .