George Polya: "Dalam "commentatio" (catatan disajikan kepada...

"Dalam "commentatio" (catatan disajikan kepada Akademi Rusia) di mana teorinya tentang polyhedra (tentang jumlah wajah, tepi dan simpul) pertama kali diterbitkan Euler tidak memberikan bukti. Di tempat bukti, ia menawarkan argumen induktif: ia memverifikasi hubungan dalam berbagai kasus khusus. Ada sedikit keraguan bahwa ia juga menemukan teorema itu, seperti banyak hasil lainnya, secara induktif."

--- George Polya

Versi Bahasa Inggris

In the "commentatio" (note presented to the Russian Academy) in which his theorem on polyhedra (on the number of faces, edges and vertices) was first published Euler gives no proof. In place of a proof, he offers an inductive argument: he verifies the relation in a variety of special cases. There is little doubt that he also discovered the theorem, as many of his other results, inductively.