Graph theory was essentially invented by, for 10 points, what Swiss mathematician and namesake of a constant about equal to 2.718, called e?
This man found the sum of the squares of the reciprocals of all natural numbers, thus solving the Basel problem, to be pi²/6 ["pi squared over six"]. The limiting difference between the natural log function and the harmonic series is a constant named for him and Mascheroni [mas-kair-OH-nee]. In 1736, he proved that no (*) path crossed each of the Pregel River's seven bridges in Konigsberg exactly once. Graph theory was essentially invented by, for 10 points, what Swiss mathematician and namesake of a constant about equal to 2.718, called e?
This man found the sum of the squares of the reciprocals of all natural numbers, thus solving the Basel problem, to be pi²/6 ["pi squared over six"].
Leonhard (Paul) Euler [OY-lur]