Matematiikan historiassa 3. huhtikuuta

Huhtikuun 3. päivänä vuonna 1736 Euler vastasi 9. päivänä maaliskuuta saamaansa kirjeeseen, joka haastoi hänet ratkaisemaan Königsbergin siltaongelmaa. "Ei matemaattinen ongelma ..."

"... Thus you see, most noble Sir, how this type of solution bears little relationship to mathematics, and I do not understand why you expect a mathematician to produce it, rather than anyone else, for the solution is based on reason alone, and its discovery does not depend on any mathematical principle. Because of this, I do not know why even questions which bear so little relationship to mathematics are solved more quickly by mathematicians than by others. In the meantime, most noble Sir, you have assigned this question to the geometry of position, but I am ignorant as to what this new discipline involves, and as to which types of problem Leibniz and Wolff expected to see expressed in this way ... "