Leonhard Euler

Leonhard Euler ( OY-lər; German: [ˈɔʏlɐ] (listen); 15 April 1707 - 18 September 1783) was a Swiss mathematician, physicist, astronomer, geographer, logician and engineer who founded the studies of graph theory and topology and made pioneering and influential discoveries in many other branches of mathematics such as analytic number theory, comple...