Peter Lax, whose work at the intersection of mathematical theory and application redefined how scientists used new computing technology to solve the technical problems of the Cold War, from designing aircraft and weapons to predicting the weather, died on May 16 at his home in Manhattan. He was 99.

As the computer age was dawning, Dr. Lax, a native of Hungary, led the way in figuring out how the new technology could be harnessed to mathematics for the purpose of analyzing complex phenomena in nature, technology and warfare. His theoretical breakthroughs and his leadership in developing large-scale computing infrastructure produced new ways to characterize and predict phenomena as varied as storm fronts, shock waves and stock prices.

“Mathematics is a broad subject,” he said. “It is true that nobody can know it all, or even nearly all. It is also true that as mathematics develops, things are simplified and unusual connections appear.”