Theodore E. Harris was an
American

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

  mathematician

Mathematician

A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....

 known for his research on stochastic process

Stochastic process

In probability theory, a stochastic process , or sometimes random process, is the counterpart to a deterministic process...

es, including such areas as general state-space Markov chain

Markov chain

A Markov chain, named after Andrey Markov, is a mathematical system that undergoes transitions from one state to another, between a finite or countable number of possible states. It is a random process characterized as memoryless: the next state depends only on the current state and not on the...

s (often
now called Harris chains), the theory of branching
processes

Branching process

In probability theory, a branching process is a Markov process that models a population in which each individual in generation n produces some random number of individuals in generation n + 1, according to a fixed probability distribution that does not vary from individual to...

 and stochastic models of interacting particle systems such as the
contact process.

He received his Ph.D. at Princeton University

Princeton University

Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....

 in 1947 under advisor Samuel Wilks

Samuel S. Wilks

Samuel Stanley Wilks was an American mathematician and academic who played an important role in the development of mathematical statistics, especially in regard to practical applications....

. From 1947 until 1966 he worked for the Rand
corporation

RAND

RAND Corporation is a nonprofit global policy think tank first formed to offer research and analysis to the United States armed forces by Douglas Aircraft Company. It is currently financed by the U.S. government and private endowment, corporations including the healthcare industry, universities...

, 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

University of Southern California

The University of Southern California is a private, not-for-profit, nonsectarian, research university located in Los Angeles, California, United States. USC was founded in 1880, making it California's oldest private research university...

.

He was elected to the United States National Academy of Sciences

United States National Academy of Sciences

The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

in 1988.

Books

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

Papers

• Harris, T. E. "Contact interactions on a lattice". Annals Probability 2 (1974) pp. 969–988.