Roger Charles Alperin (January 8, 1947 – November 21, 2019) was an American mathematician, best known for his work in
group theory
In abstract algebra, group theory studies the algebraic structures known as group (mathematics), groups.
The concept of a group is central to abstract algebra: other well-known algebraic structures, such as ring (mathematics), rings, field ...
, including its connections with
geometry
Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is c ...
and
topology
In mathematics, topology (from the Greek words , and ) is concerned with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing ho ...
. He was a professor at the
University of Oklahoma
, mottoeng = "For the benefit of the Citizen and the State"
, type = Public research university
, established =
, academic_affiliations =
, endowment = $2.7billion (2021)
, pr ...
and at
San Jose State University
San José State University (San Jose State or SJSU) is a public university in San Jose, California. Established in 1857, SJSU is the oldest public university on the West Coast and the founding campus of the California State University (CSU) sy ...
.
Education and career
Alperin was born on January 8, 1947, in
Cambridge, Massachusetts
Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. As part of the Greater Boston, Boston metropolitan area, the cities population of the 2020 United States Census, 2020 U.S. census was 118,403, making it the fourth most ...
. He received a bachelor's degree from the
University of Chicago
The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...
, and his PhD from
Rice University
William Marsh Rice University (Rice University) is a private research university in Houston, Texas. It is on a 300-acre campus near the Houston Museum District and adjacent to the Texas Medical Center. Rice is ranked among the top universit ...
in 1973. His thesis was supervised by
Stephen M. Gersten
Stephen M. Gersten (born 2 December 1940) was an American mathematician, specializing in finitely presented groups and their geometric properties.
Gersten graduated in 1961 with an AB from Princeton University and in 1965 with a PhD from Trinity ...
, and was titled ''Whitehead Torsion of Finite Abelian Groups''. After temporary positions at Brown University, Haverford College, and
Washington University in St. Louis
Washington University in St. Louis (WashU or WUSTL) is a private research university with its main campus in St. Louis County, and Clayton, Missouri. Founded in 1853, the university is named after George Washington. Washington University i ...
, Alperin took a permanent position at the
University of Oklahoma
, mottoeng = "For the benefit of the Citizen and the State"
, type = Public research university
, established =
, academic_affiliations =
, endowment = $2.7billion (2021)
, pr ...
in 1978. He was eventually promoted to full professor at the University of Oklahoma, but resigned his position to move to California in 1987. Upon moving to California, he found a position at San Jose State University, which he held until his retirement in 2015.
Alperin died on November 21, 2019, at his home in
Carlsbad, California
Carlsbad is a coastal city in the North County region of San Diego County, California, United States. The city is south of downtown Los Angeles and north of downtown San Diego. As of the 2020 census, the population of the city was 114,746. ...
.
Research
Alperin's work on real trees in the 80s (partly joint with
geometric group theory
Geometric group theory is an area in mathematics devoted to the study of finitely generated groups via exploring the connections between algebraic properties of such groups and topological and geometric properties of spaces on which these group ...
. Alperin has also done foundational work on the
mathematical theory
A mathematical theory is a mathematical model of a branch of mathematics that is based on a set of axioms. It can also simultaneously be a body of knowledge (e.g., based on known axioms and definitions), and so in this sense can refer to an area ...
of
origami
) is the Japanese art of paper folding. In modern usage, the word "origami" is often used as an inclusive term for all folding practices, regardless of their culture of origin. The goal is to transform a flat square sheet of paper into a f ...