Izzy´s eBook Library - The Fairy Chessmen by Henry Kuttner, Catherine Lucile Moore

The Fairy Chessmen
Author: Henry Kuttner
Pseudonym: Lewis Padget

A mathematician whose research involves a type of chess played with variable rules ("fairy chess") is the only one able to solve an "equation from the future" in which the constants are treated as variables that the "bad guys" are going to use to win World War III. Apparently, the fact that the equation involves lots of variables is supposed to be able to drive most mathematicians crazy.