Thomas Milton Liggett (March 29, 1944 – May 12, 2020) was a mathematician at the

University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...

. He worked in

probability theory Probability theory is the branch of mathematics concerned with probability. Although there are several different probability interpretations, probability theory treats the concept in a rigorous mathematical manner by expressing it through a set o ...

, specializing in interacting particle systems.

Early life

Thomas Milton Liggett was born on March 29, 1944, in

Danville, Kentucky Danville is a home rule-class city in Boyle County, Kentucky, United States. It is the seat of its county. The population was 17,236 at the 2020 Census. Danville is the principal city of the Danville Micropolitan Statistical Area, which includes ...

. Liggett moved at the age of two with his missionary parents to Latin America, where he was educated in Bueno Aires, Argentina and

San Juan, Puerto Rico San Juan (, , ; Spanish for "Saint John") is the capital city and most populous municipality in the Commonwealth of Puerto Rico, an unincorporated territory of the United States. As of the 2020 census, it is the 57th-largest city under the jur ...

. He graduated from

Oberlin College Oberlin College is a Private university, private Liberal arts colleges in the United States, liberal arts college and conservatory of music in Oberlin, Ohio. It is the oldest Mixed-sex education, coeducational liberal arts college in the United S ...

with a

Bachelor of Arts Bachelor of arts (BA or AB; from the Latin ', ', or ') is a bachelor's degree awarded for an undergraduate program in the arts, or, in some cases, other disciplines. A Bachelor of Arts degree course is generally completed in three or four years ...

in 1965, where he was influenced towards

probability Probability is the branch of mathematics concerning numerical descriptions of how likely an Event (probability theory), event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and ...

by Samuel Goldberg (b. 1925), an ex-student of

William Feller William "Vilim" Feller (July 7, 1906 – January 14, 1970), born Vilibald Srećko Feller, was a Croatian-American mathematician specializing in probability theory. Early life and education Feller was born in Zagreb to Ida Oemichen-Perc, a Croa ...

. He moved to

Stanford Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is considere ...

, taking classes with

Kai Lai Chung Kai Lai Chung (traditional Chinese: 鍾開萊; simplified Chinese: 钟开莱; September 19, 1917 – June 2, 2009) was a Chinese-American mathematician known for his significant contributions to modern probability theory. Biography Chung wa ...

, and writing his thesis, ''Weak Convergence of Conditioned Sums of Independent Random Vectors'', in 1969 with advisor

Samuel Karlin Samuel Karlin (June 8, 1924 – December 18, 2007) was an American mathematician at Stanford University in the late 20th century. Biography Karlin was born in Janów, Poland and immigrated to Chicago as a child. Raised in an Orthodox Jewish hous ...

on problems associated with the invariance principle. He graduated with a

Master of Science A Master of Science ( la, Magisterii Scientiae; abbreviated MS, M.S., MSc, M.Sc., SM, S.M., ScM or Sc.M.) is a master's degree in the field of science awarded by universities in many countries or a person holding such a degree. In contrast to ...

in 1966 and a

Doctor of Philosophy A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common Academic degree, degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields ...

in 1969.

Career

Liggett joined the faculty at

UCLA The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...

in 1969, where he spent his entire career. He became a professor in the mathematics department in 1976, and served as department chair from 1991 to 1994. He retired in 2011, but remained active within the department. He was the advisor of

Norman Matloff Norman Saul Matloff (born December 16, 1948) is an American professor of computer science at the University of California, Davis. Early life Norman Saul Matloff was born on December 16, 1948. Matloff received his Doctor of Philosophy degree in 1 ...

. Liggett had contributed to numerous areas of

, including subadditive

ergodic theory Ergodic theory (Greek: ' "work", ' "way") is a branch of mathematics that studies statistical properties of deterministic dynamical systems; it is the study of ergodicity. In this context, statistical properties means properties which are expres ...

random graphs In mathematics, random graph is the general term to refer to probability distributions over graphs. Random graphs may be described simply by a probability distribution, or by a random process which generates them. The theory of random graphs li ...

renewal theory Renewal theory is the branch of probability theory that generalizes the Poisson process for arbitrary holding times. Instead of exponentially distributed holding times, a renewal process may have any independent and identically distributed (IID) ho ...

, and was best known for his pioneering work on interacting particle systems, including the

contact process The contact process is the current method of producing sulfuric acid in the high concentrations needed for industrial processes. Platinum was originally used as the catalyst for this reaction; however, as it is susceptible to reacting with arsenic ...

, the

voter model In the mathematical theory of probability, the voter model is an interacting particle system introduced by Richard A. Holley and Thomas M. Liggett in 1975. One can imagine that there is a "voter" at each point on a connected graph, where the c ...

, and the exclusion process. His two books in this field have been influential. Liggett was the managing editor of the

Annals of Probability The ''Annals of Probability'' is a leading peer-reviewed probability journal published by the Institute of Mathematical Statistics, which is the main international society for researchers in the areas probability and statistics. The journal was sta ...

from 1985–1987. He held a

Sloan Research Fellowship The Sloan Research Fellowships are awarded annually by the Alfred P. Sloan Foundation since 1955 to "provide support and recognition to early-career scientists and scholars". This program is one of the oldest of its kind in the United States. ...

from 1973–1977, and a

Guggenheim Fellowship Guggenheim Fellowships are grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation to those "who have demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the ar ...

from 1997–1998. He was the Wald Memorial Lecturer of the

Institute of Mathematical Statistics The Institute of Mathematical Statistics is an international professional and scholarly society devoted to the development, dissemination, and application of statistics and probability. The Institute currently has about 4,000 members in all parts o ...

in 1996, and was elected to the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...

in 2008. He had been elected to the American Academy of Arts & Sciences in 2012, and in 2012 he also became 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, ...

Personal life

Liggett married Christina Marie Goodale on August 19, 1972. They had two children, Timothy and Amy. Liggett died on May 12, 2020, in

Los Angeles Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

Notes

External links

* {{DEFAULTSORT:Liggett, Thomas M. 2020 deaths 1944 births 20th-century American mathematicians 21st-century American mathematicians People from Danville, Kentucky Oberlin College alumni Stanford University alumni University of California, Los Angeles faculty Probability theorists Fellows of the American Mathematical Society Members of the United States National Academy of Sciences Annals of Probability editors