Lobachevsky, Nikolay Ivanovich[lobachefskee]
Mathematician, born in Nizhni Novgorod, Russia. He became professor at Kazan in 1816, where he spent the rest of his life. In the 1820s he developed a theory of non-Euclidean geometry in which Euclid's parallel postulate did not hold. A similar theory was discovered almost simultaneously and independently by Jénos Bolyai.