Michael Fredric Sipser (born September 17, 1954) is an American
theoretical computer scientist who has made early contributions to
computational complexity theory
In theoretical computer science and mathematics, computational complexity theory focuses on classifying computational problems according to their resource usage, and explores the relationships between these classifications. A computational problem ...
. He is a
professor
Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...
of
applied mathematics
Applied mathematics is the application of mathematics, mathematical methods by different fields such as physics, engineering, medicine, biology, finance, business, computer science, and Industrial sector, industry. Thus, applied mathematics is a ...
and was the dean of science at the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
.
Biography
Sipser was born and raised in Brooklyn, New York and moved to Oswego, New York when he was 12 years old. He earned his BA in mathematics from
Cornell University
Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
in 1974 and his PhD in engineering from the
University of California at Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a public land-grant research university in Berkeley, California, United States. Founded in 1868 and named after the Anglo-Irish philosopher George Berkele ...
in 1980 under the direction of
Manuel Blum
Manuel Blum (born 26 April 1938) is a Venezuelan-born American computer scientist who received the Turing Award in 1995 "In recognition of his contributions to the foundations of computational complexity theory and its application to cryptography ...
.
He joined MIT's
Laboratory for Computer Science as a research associate in 1979 and then was a Research Staff Member at
IBM Research
IBM Research is the research and development division for IBM, an American Multinational corporation, multinational information technology company. IBM Research is headquartered at the Thomas J. Watson Research Center in Yorktown Heights, New York ...
in San Jose. In 1980, he joined the MIT faculty. He spent the 1985–1986 academic year on the faculty of the University of California at Berkeley and then returned to MIT. From 2004 until 2014, he served as head of the MIT Mathematics department. He was appointed Interim Dean of the
MIT School of Science in 2013 and Dean in 2014. He served as Dean until 2020, when he was followed by
Nergis Mavalvala. He is a fellow of the American Academy of Arts and Sciences. In 2015 he was elected as a fellow of the
American Mathematical Society
The American Mathematical Society (AMS) is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, and serves the national and international community through its publications, meetings, ...
"for contributions to complexity theory and for leadership and service to the mathematical community."
He was elected as an
ACM Fellow in 2017.
Scientific career
Sipser specializes in
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...
s and
complexity theory, specifically efficient error correcting codes, interactive proof systems, randomness, quantum computation, and establishing the inherent computational difficulty of problems. He introduced the method of probabilistic restriction for proving super-polynomial lower bounds on
circuit complexity
In theoretical computer science, circuit complexity is a branch of computational complexity theory in which Boolean functions are classified according to the size or depth of the Boolean circuits that compute them. A related notion is the circui ...
in a paper joint with Merrick Furst and
James B. Saxe. Their result was later improved to be an exponential lower bound by
Andrew Yao and
Johan Håstad.
In an early
derandomization theorem, Sipser showed that
BPP is contained in the
polynomial hierarchy
In computational complexity theory, the polynomial hierarchy (sometimes called the polynomial-time hierarchy) is a hierarchy of complexity classes that generalize the classes NP and co-NP. Each class in the hierarchy is contained within PSPACE. ...
, subsequently improved by
Peter Gács and
Clemens Lautemann to form what is now known as the
Sipser–Gács–Lautemann theorem. Sipser also established a connection between
expander graph
In graph theory, an expander graph is a sparse graph that has strong connectivity properties, quantified using vertex, edge or spectral expansion. Expander constructions have spawned research in pure and applied mathematics, with several appli ...
s and derandomization. He and his PhD student
Daniel Spielman introduced
expander codes, an application of expander graphs. With fellow graduate student David Lichtenstein, Sipser proved that
Go is
PSPACE
In computational complexity theory, PSPACE is the set of all decision problems that can be solved by a Turing machine using a polynomial amount of space.
Formal definition
If we denote by SPACE(''f''(''n'')), the set of all problems that can ...
hard.
In quantum computation theory, he introduced the
adiabatic algorithm jointly with
Edward Farhi,
Jeffrey Goldstone, and Samuel Gutmann.
Sipser has long been interested in the
P versus NP problem
The P versus NP problem is a major unsolved problem in theoretical computer science. Informally, it asks whether every problem whose solution can be quickly verified can also be quickly solved.
Here, "quickly" means an algorithm exists that ...
. In 1975, he wagered an ounce of gold with
Leonard Adleman that the problem would be solved with a proof that P ≠ NP by the end of the 20th century. Sipser sent Adleman an
American Gold Eagle
The American Gold Eagle is an official gold bullion coin of the United States. Authorized under the Gold Bullion Coin Act of 1985, it was first released by the United States Mint in 1986. Because the term "eagle" also is the official United St ...
coin in 2000 because the problem remained (and remains) unsolved.
Notable books
Sipser is the author of ''
Introduction to the Theory of Computation'',
a textbook for
theoretical computer science
Theoretical computer science is a subfield of computer science and mathematics that focuses on the Abstraction, abstract and mathematical foundations of computation.
It is difficult to circumscribe the theoretical areas precisely. The Associati ...
.
Personal life
Sipser lives in Cambridge, Massachusetts with his wife, Ina, and has two children: a daughter, Rachel, who graduated from New York University, and a younger son, Aaron, who graduated from MIT.
References
External links
Personal homepage at MIT
{{DEFAULTSORT:Sipser, Michael
1954 births
Living people
20th-century American mathematicians
21st-century American mathematicians
University of California, Berkeley alumni
Massachusetts Institute of Technology School of Science faculty
American theoretical computer scientists
Fellows of the American Mathematical Society
Fellows of the American Academy of Arts and Sciences
2017 fellows of the Association for Computing Machinery
American computer science educators
American quantum information scientists
Cornell University alumni
20th-century American engineers
21st-century American engineers