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 university, public Land-grant university, land-grant research university in Los Angeles, California, United States. Its academic roots were established in 1881 as a normal school the ...

. He worked in

probability theory Probability theory or probability calculus 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 expre ...

, specializing in

interacting particle systems In probability theory, an interacting particle system (IPS) is a stochastic process (X(t))_ on some configuration space \Omega= S^G given by a site space, a countably-infinite-order graph G and a local state space, a compact metric space S ...

Early life

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

Danville, Kentucky Danville is a list of Kentucky cities, home rule-class city and the county seat of Boyle County, Kentucky, United States. The population was 17,236 at the 2020 United States census, 2020 census. Danville is the principal city of the Danville Micr ...

. 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 the Baptist, John") is the capital city and most populous Municipalities of Puerto Rico, municipality in the Commonwealth (U.S. insular area), Commonwealth of Puerto Rico, an unincorporated territory of the ...

. 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, United States. Founded in 1833, it is the oldest Mixed-sex education, coeducational lib ...

with a

Bachelor of Arts A Bachelor of Arts (abbreviated B.A., BA, A.B. or AB; from the Latin ', ', or ') is the holder of a bachelor's degree awarded for an undergraduate program in the liberal arts, or, in some cases, other disciplines. A Bachelor of Arts deg ...

in 1965, where he was influenced towards

probability Probability is a branch of mathematics and statistics concerning events and numerical descriptions of how likely they are to occur. The probability of an event is a number between 0 and 1; the larger the probability, the more likely an e ...

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 Cro ...

. He moved to

Stanford Leland Stanford Junior University, commonly referred to as Stanford University, is a private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth governor of and th ...

, 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. Education and career Karlin was born in Janów, Poland and immigrated to Chicago as a child. Raised in an Orthodo ...

on problems associated with the

invariance principle In cognitive linguistics, the invariance principle is a simple attempt to explain similarities and differences between how an idea is understood in "ordinary" usage, and how it is understood when used as a conceptual metaphor. Kövecses (2002: 102 ...

. He graduated with a

Master of Science A Master of Science (; abbreviated MS, M.S., MSc, M.Sc., SM, S.M., ScM or Sc.M.) is a master's degree. In contrast to the Master of Arts degree, the Master of Science degree is typically granted for studies in sciences, engineering and medici ...

in 1966 and a

Doctor of Philosophy A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of Postgraduate education, graduate study and original resear ...

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, United States. Its academic roots were established in 1881 as a normal school then known as the southern branch of the C ...

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 ...

and

Amber L. Puha Amber Lynn Puha is an American mathematician and educator at California State University San Marcos. Her research concerns probability theory and stochastic processes. Early life and education She earned a B.A. in mathematics at University of C ...

. Liggett had contributed to numerous areas of

, including subadditive

ergodic theory Ergodic theory is a branch of mathematics that studies statistical properties of deterministic dynamical systems; it is the study of ergodicity. In this context, "statistical properties" refers to properties which are expressed through the behav ...

random graphs In mathematics, random graph is the general term to refer to probability distributions over Graph (discrete mathematics), graphs. Random graphs may be described simply by a probability distribution, or by a random process which generates them. ...

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) h ...

, and was best known for his pioneering work on

, including the

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

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

Annals of Probability ''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 started ...

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 Grant (money), grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation, endowed by the late Simon Guggenheim, Simon and Olga Hirsh Guggenheim. These awards are bestowed upon indiv ...

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 ...

in 1996, and was elected to the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, 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 ...

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, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...

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 American probability theorists Fellows of the American Mathematical Society Members of the United States National Academy of Sciences Annals of Probability editors