Complex sentence: Ivan Ivanovich Privalov (11 February, 1891, Nizhniy Lomov, Penza guberniya--13 July, 1941, Moscow) was a Russian mathematician best known for his work on analytical functions.
Split into simpler sentences: Ivan Ivanovich Privalov (11 February, 1891--13 July, 1941) was a Russian mathematician. He is best known for his work on analytical functions.