Roger Charles Alperin (January 8, 1947 – November 21, 2019) was an American mathematician, best known for his work in group theory, including its connections with geometry and topology.
His thesis was supervised by Stephen M. Gersten, and was titled Whitehead Torsion of Finite Abelian Groups.
[4] He was eventually promoted to full professor at the University of Oklahoma, but resigned his position to move to California in 1987.
[4] Upon moving to California, he found a position at San Jose State University, which he held until his retirement in 2015.
[4] Alperin's work on real trees in the 80s (partly joint with Hyman Bass and Kenneth Moss) helped to stimulate interest in these objects, and helped establish them as a basic tool in geometric group theory.