Alfred Horn (February 17, 1918 – April 16, 2001) 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 ...

notable for his work in

lattice theory A lattice is an abstract structure studied in the mathematical subdisciplines of order theory and abstract algebra. It consists of a partially ordered set in which every pair of elements has a unique supremum (also called a least upper bou ...

and

universal algebra Universal algebra (sometimes called general algebra) is the field of mathematics that studies algebraic structures themselves, not examples ("models") of algebraic structures. For instance, rather than take particular groups as the object of stu ...

. His 1951 paper "On sentences which are true of direct unions of algebras" described

Horn clause In mathematical logic and logic programming, a Horn clause is a logical formula of a particular rule-like form which gives it useful properties for use in logic programming, formal specification, and model theory. Horn clauses are named for the log ...

s and Horn sentences, which later would form the foundation of

logic programming Logic programming is a programming paradigm which is largely based on formal logic. Any program written in a logic programming language is a set of sentences in logical form, expressing facts and rules about some problem domain. Major logic pro ...

Biography

Horn was born on

Lower East Side, Manhattan The Lower East Side, sometimes abbreviated as LES, is a historic neighborhood in the southeastern part of Manhattan in New York City. It is located roughly between the Bowery and the East River from Canal to Houston streets. Traditionally an im ...

. His parents were both

deaf Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written ...

, and his father died when Horn was three years old. At this point, the children moved in with their grandparents on the mother's side. They would later move to

Brooklyn Brooklyn () is a borough of New York City, coextensive with Kings County, in the U.S. state of New York. Kings County is the most populous county in the State of New York, and the second-most densely populated county in the United States, be ...

where Horn spent most of his childhood, raised by his extended family. Horn attended the City College of New York, and later,

New York University New York University (NYU) is a private research university in New York City. Chartered in 1831 by the New York State Legislature, NYU was founded by a group of New Yorkers led by then- Secretary of the Treasury Albert Gallatin. In 1832, th ...

where he earned a

Master's degree A master's degree (from Latin ) is an academic degree awarded by universities or colleges upon completion of a course of study demonstrating mastery or a high-order overview of a specific field of study or area of professional practice.

in mathematics. He went on to earn his

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

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...

in 1946. A year later, he started work 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 S ...

, where he stayed until his retirement in 1988. He died in 2001 in

Pacific Palisades, Los Angeles Pacific Palisades is a neighborhood in the Westside region of Los Angeles, California, situated about west of Downtown Los Angeles. Pacific Palisades was formally founded in 1921 by a Methodist organization, and in the years that followed bec ...

after eight years of battling prostate cancer.

References

Alfred Horn, Palisadian Since 1954 and Noted UCLA Math Professor
– obituary from UCLA
Publications of Alfred Horn
– a list compiled by

Dimiter Skordev Dimiter Skordev ( bg, Димитър Скордев) (born 1936 in Sofia) is a professor in the Department of Mathematical Logic and Applications, Faculty of Mathematics and Computer Science at the University of Sofia. Chairman of the department ...

Alfred Horn
– the information about him in the

Mathematics Genealogy Project The Mathematics Genealogy Project (MGP) is a web-based database for the academic genealogy of mathematicians.. By 31 December 2021, it contained information on 274,575 mathematical scientists who contributed to research-level mathematics. For a ty ...

{{DEFAULTSORT:Horn, Alfred 20th-century American mathematicians American logicians Lattice theorists 1918 births 2001 deaths City University of New York alumni New York University alumni University of California, Berkeley alumni University of California, Los Angeles faculty Philosophers from New York (state) Philosophers from California People from the Lower East Side People from Brooklyn