Walter Savitch

Walter John Savitch (February 21, 1943 – February 1, 2021) was an American computer scientist. He was best known for defining the NL (nondeterministic logarithmic space) and for Savitch's theorem. He was a professor at the University of California, San Diego.
Savitch died on February 1, 2021 in San Diego, California from problems caused by Parkinson's disease, aged 77.