FTP, who was this Swiss mathematicisn whose namesake identity involves the number e?
This mathematician's "characteristic" is defined to be the number of vertices of a graph minus the number of edges plus the number of faces. He introduced the symbols of pi and sigma to mathematics, and his phi function tells the amount of numbers between 1 and n relatively prime to n. He solved the Seven Bridges of Konigsburg problem, but went completely blind by 1766. FTP, who was this Swiss mathematicisn whose namesake identity involves the number e?
This mathematician's "characteristic" is defined to be the number of vertices of a graph minus the number of edges plus the number of faces.
Leonhard Euler