Leonhard Euler

Who is Leonhard Euler?

Leonhard Euler was a Swiss mathematician, physicist, astronomer, and engineer born in Basel, widely regarded as one of the greatest mathematicians in history. He studied at the University of Basel under Johann Bernoulli. Euler spent much of his career at the academies of Saint Petersburg and Berlin. He made foundational contributions across an extraordinary range of fields, including calculus, graph theory, number theory, mechanics, optics, and astronomy. He introduced much of modern mathematical notation, including the function notation f(x), the constant e, the symbol for summation, and the use of the letter i for the imaginary unit. Euler's identity and Euler's formula in complex analysis bear his name, as do the Euler characteristic, Euler's theorem, and the solution to the Seven Bridges of Königsberg problem that founded graph theory. Despite losing his sight in later life, he remained astonishingly productive, dictating results until his death in Saint Petersburg.

Sources: Leonhard Euler, 'Introductio in analysin infinitorum', 1748 · Leonhard Euler, 'Solutio problematis ad geometriam situs pertinentis' (Seven Bridges of Königsberg), 1736