- 1707-1783. Swiss mathematician and physicist.
- Founded graph theory by solving the Seven Bridges of Königsberg problem (1736).
- The most prolific mathematician in history, contributing to calculus, number theory, topology, mechanics, optics, and astronomy.
- Introduced modern notation: e, i, pi, sigma summation, f(x) function notation.
- Euler’s identity (e^(i*pi) + 1 = 0) unifies five fundamental constants in a single equation.
- His work on graphs and networks is the mathematical foundation for knowledge graph structure, link analysis, and cyber ranking.