Radivoj Kašanin or Radivoje Kašanin (Beli Manastir, then part of the Habsburg monarchy, 21 May 1892 — Belgrade, Yugoslavia, 30 October 1989) was a Serbian mathematician, university professor, and member of the Serbian Academy of Arts and Sciences. His mentor was the famed Balkan mathematician Mihailo Petrović Alas.Radivoje Kašanin is regarded as a talented mathematician and scholar of natural sciences with a wide scientific culture. As for his profound and diversified knowledge in many areas of mathematics, mechanics, and astronomy he could be considered as Serbia's last encyclopedist. Radivoje Kašanin achieved success in many fields of his profession: theory of differential equations, the theory of complex functions, analysis, geometry, interpolation and approximation, mechanics, astronom