The original version of this story appeared in Quanta Magazine. Calculus is a powerful mathematical tool. But for hundreds of years after its invention in the 17th century, it stood on a shaky ...

In the late 19th century, Karl Weierstrass invented a fractal-like function that was decried as nothing less than a “deplorable evil.” In time, it would transform the foundations of mathematics.

Back in 1948, the journal Physical Review published a paper entitled “Space-Time Approach to Quantum Electrodynamics” by a young physicist named R.P. Feynman at Cornell University. The paper described ...

The Rocky Mountain Journal of Mathematics, Vol. 39, No. 5 (2009), pp. 1467-1496 (30 pages) In this expository paper, we describe the Weyl calculus for bounded, self-adjoint operators acting on a ...