Chandler Davis

Horace Chandler Davis (August 12, 1926 – September 24, 2022) was an American-Canadian mathematician, writer, educator, and left-wing political activist.

The socialist magazine Jacobin described Davis as "an internationally esteemed mathematician, a minor science fiction writer of note, and among the most celebrated political prisoners in the United States during the years of the high Cold War."

Horace Chandler Davis, known as "Chan" by friends, was born on August 12, 1926, in Ithaca, New York, to parents Horace Bancroft Davis and Marian Rubins, both members of the Communist Party USA (CPUSA).

He joined the Young Pioneers of America while in elementary school.

Because of their politics, his parents moved frequently, so that Davis spent a year of his childhood in Brazil.

In 1942, age 16, he received a Harvard National Scholarship.

At Harvard, he joined the Astounding Science-Fiction Fanclub, whose members included: John B. Michel, Frederik Pohl, Isaac Asimov, and Donald Wollheim.

In 1943, Davis joined the Communist Party USA but left soon after so he could join the US Navy for officers training.

In 1945, Davis graduated Harvard early and also received a commission from Naval Reserve Midshipman's School and spent a year in the US Navy as a minesweeper.

In 1946, he returned to Harvard as a graduate student in Mathematics, rejoined the CPUSA, and joined the Federation of American Scientists, founded by former members of the Manhattan Project.

Davis began his writing career in Astounding Science Fiction in 1946.

From 1946 through 1962 he produced a spate of science fiction stories, mostly published there.

One of the earliest, published May 1946, was The Nightmare, later the lead story in A Treasury of Science Fiction, edited by Groff Conklin; it argued for a national policy of decentralizing industry to evade nuclear attacks by terrorists.

In 1948, he supported Henry A. Wallace, Progressive Party candidate for the 1948 United States presidential election.

In 1950, Davis received a doctorate in Mathematics from Harvard University.

In 1950, Davis turned down an offer from the University of California Los Angeles (UCLA) due to loyalty oath requirements and accepted a position as instructor at the University of Michigan (UM).

Davis left the CPUSA the following year.

In 1953, Davis received a subpoena to appear before the House Un-American Activities Committee (HUAC).

In 1954, UM suspended Davis, Clement Markert, and Mark Nickerson for refusing to cooperate with HUAC hearings held in Lansing, Michigan.

Makert and Nickerson pled under the Fifth Amendment (right to avoid self-incrimination), while Davis pled the First Amendment (right to free speech).

He hoped to establish a precedent that HUAC could not question witnesses on their political affiliations, but the US Supreme Court in 1959 refused to hear his case.

After years of appeals, in 1960, Davis received a six-month jail sentence, served at a prison in Danbury, Connecticut.

In 1962, Davis accepted a teaching position at the University of Toronto.

He specialized in algebra and operator theory (a branch of functional analysis).

In the Mathematics Genealogy Project, he is listed as having 15 PhD (1964-2001), and 213 PhD descendants of his former doctoral students, with 107 being of them from his student John Benedetto (PhD 1964).

He was one of the co-Editors-in-Chief of the Mathematical Intelligencer.

In 1968, the Warsaw Pact invasion of Czechoslovakia ended Davis' CPUSA membership for good.

He remained a political activist.

For example, in 1971, he traveled to North Vietnam with other mathematicians including Laurent Schwartz.

He also was an advocate for Palestinian rights.

In July 2022, he publicly supported Russian mathematician Azat Miftakhov.

Davis' principal research investigations involved linear algebra and operator theory in Hilbert spaces.

Furthermore, he made contributions to numerical analysis, geometry, and algebraic logic.

He is one of the eponyms of the Davis–Kahan theorem and Bhatia–Davis inequality (along with Rajendra Bhatia).

The Davis–Kahan–Weinberger dilation theorem is one of the landmark results in the dilation theory of Hilbert space operators and has found applications in many different areas.

A PhD thesis titled "Backward Perturbation and Sensitivity Analysis of Structured Polynomial Eigenomial Eigenvalue Problem" is dedicated to this theorem.

Davis wrote around eighty research papers in mathematics.

Davis was a professor in the mathematics department of University of Michigan, working alongside Wilfred Kaplan.

In 2012 he became a fellow of the American Mathematical Society.

He was part of the 2019 class of fellows of the Association for Women in Mathematics.