Theodore Edward Harris (11 January 1919 – 3 November 2005) was an American

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

known for his research on

stochastic process In probability theory and related fields, a stochastic () or random process is a mathematical object usually defined as a family of random variables. Stochastic processes are widely used as mathematical models of systems and phenomena that appea ...

es, including such areas as general state-space

Markov chain A Markov chain or Markov process is a stochastic model describing a sequence of possible events in which the probability of each event depends only on the state attained in the previous event. Informally, this may be thought of as, "What happe ...

s (often now called

Harris chain In the mathematical study of stochastic processes, a Harris chain is a Markov chain where the chain returns to a particular part of the state space an unbounded number of times. Harris chains are regenerative processes and are named after Theodo ...

s), the theory of

branching process In probability theory, a branching process is a type of mathematical object known as a stochastic process, which consists of collections of random variables. The random variables of a stochastic process are indexed by the natural numbers. The origi ...

es and stochastic models of interacting particle systems such as 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

Harris inequality In mathematics, the Fortuin–Kasteleyn–Ginibre (FKG) inequality is a correlation inequality, a fundamental tool in statistical mechanics and probabilistic combinatorics (especially random graphs and the probabilistic method), due to . Informa ...

statistical physics Statistical physics is a branch of physics that evolved from a foundation of statistical mechanics, which uses methods of probability theory and statistics, and particularly the Mathematics, mathematical tools for dealing with large populations ...

and

percolation theory In statistical physics and mathematics, percolation theory describes the behavior of a network when nodes or links are added. This is a geometric type of phase transition, since at a critical fraction of addition the network of small, disconnected ...

is named after him. He received his Ph.D. at

Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...

in 1947 under advisor

Samuel Wilks Sir Samuel Wilks, 1st Baronet, (2 June 1824 – 8 November 1911) was a British physician and biographer. Early life Samuel Wilks was born on 2 June 1824 in Camberwell, London, the second son of Joseph Barber Wilks, a cashier at the East India H ...

. From 1947 until 1966 he worked for the

RAND Corporation The RAND Corporation (from the phrase "research and development") is an American nonprofit global policy think tank created in 1948 by Douglas Aircraft Company to offer research and analysis to the United States Armed Forces. It is financed ...

, heading their mathematics department from 1959 to 1965. From 1966 until retirement in 1989 he was Professor of Mathematics and Electrical Engineering at

University of Southern California The University of Southern California (USC, SC, or Southern Cal) is a Private university, private research university in Los Angeles, California, United States. Founded in 1880 by Robert M. Widney, it is the oldest private research university in C ...

. He was elected to the

United States 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 1988.

Selected publications

Books

* Harris, Theodore E. "The theory of branching processes". Springer-Verlag, Berlin. (1963) 230 pp.

Papers

* *

References

{{DEFAULTSORT:Harris, Ted 20th-century American mathematicians 21st-century American mathematicians Members of the United States National Academy of Sciences Probability theorists Presidents of the Institute of Mathematical Statistics 1919 births 2005 deaths