soon after arriving at göttingen, however, she demonstrated her capabilities by proving the theorem now known as noether's theorem, which shows that a conservation law is associated with any differentiable symmetry of a physical system. the paper was presented by a colleague, f. klein on 26 july 1918 to a meeting of the royal society of sciences at göttingen. noether presumably did not present it herself because she was not a member of the society. american physicists leon m. lederman and christopher t. hill argue in their book "symmetry and the beautiful universe" that noether's theorem is "certainly one of the most important mathematical theorems ever proved in guiding the development of modern physics, possibly on a par with the pythagorean theorem".