Complex sentence: Carlo Cercignani (June 17,1939, Teulada--January 7,2010, Milan) was an Italian mathematician known for contributions to the kinetic theory of gases, particularly, the proof of the H-theorem for polyatomic gases.
Split into simpler sentences: Carlo Cercignani (June 17,1939, Teulada--January 7,2010, Milan) was an Italian mathematician known for contributions to the kinetic theory of gases. His contributions to the study of Boltzmann's equation include the proof of the H-theorem for polyatomic gases.