Complex sentence: Nikolai Nikolaevich Luzin, (also spelled Lusin) (December 9,1883, Irkutsk--January 28,1950, Moscow), was a Soviet/Russian mathematician known for his work in descriptive set theory and aspects of mathematical analysis with strong connections to point-set topology.
Split into simpler sentences: Nikolai Nikolaevich Luzin, (also spelled Lusin) (December 9,1883, Irkutsk--January 28,1950, Moscow), was a Soviet/Russian mathematician. He was noted for his work in descriptive set theory and aspects of mathematical analysis with strong connections to point-set topology.