Borrowing from @Frost's review on Penrose, Euler is the one of the three mathematician breakers in the Ashes cycle. Euler is often known for Euler's Method, a procedure for solving differential equations in calculus. The other breaker in the cycle is Gauss.
My links were set up incorrectly, other than to Euler's Method. Penrose, Euler, and Gauss linked correctly here.
— Ketzol