|Juris Hartmanis and Richard Stearns in a photo dated May 1963. The main theorem from their paper is on the board later improved by Hennie and Stearns. Photo courtesy of Richard Stearns.|
I've mentioned this paper several times in the blog before, including as a favorite theorem. Hartmanis and Stearns first formalized and truly popularized the idea of measuring time and other resources as a function the problem size, laying the foundation for virtually every paper in computational complexity and algorithms to follow.
Both Hartmanis and Stearns wrote about those early days. The main breakthroughs for their paper started in November 1962 and on December 31 Hartmanis wrote in his logbook "This was a good year," A good year indeed.