Leonhard Euler ( / ˈ ɔɪ l ər / OY -lər , [a] German: [ˈleːɔnhaʁt ˈɔʏlɐ] ( listen ) ; [b] 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 , complex analysis , and infinitesimal calculus . He introduced much of modern mathematical terminology and notation , includin
Euler is held to be one of the greatest mathematicians in history and the greatest of the 18th century. Several great mathematicians who produced their work after Euler's death have recognised his importance in the field as shown by quotes attributed to many of them: Pierre-Simon Laplace expressed Euler's influence on mathematics by stating, "Read Euler, read Euler, he is the master of us all." [8] [c] Carl Friedrich Gauss wrote: "The study of Euler's works will remain the best school for the different fiel
Euler was also the first practitioner of graph theory (partly as a solution for the problem of the Seven Bridges of Königsberg ). He became famous for, among many other accomplishments, solving the Basel problem , after proving that the sum of the infinite series of squared integer reciprocals equaled exactly π 2 /6 , and for discovering that the sum of the numbers of vertices and faces minus edges of a polyhedron equals 2, a number now commonly known as the Euler characteristic . In the field of physics, E