Joseph Bertrand

Joseph Louis François Bertrand (French pronunciation:; 11 March 1822 – 5 April 1900) was a French mathematician and historian of science whose work emphasized number theory, differential geometry, probability theory, economics and thermodynamics.

He lends his name to various paradoxes in mathematics and economics—Bertrand's paradoxes— and to Bertrand's theorem on the stability of celestial orbits.