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, mathematical structure, structure, space, Mathematica ...

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 in general, not specific types of algebraic structures. For instance, rather than considering groups or rings as the object of stud ...

. 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 that gives it useful properties for use in logic programming, formal specification, universal algebra and model theory. Horn clauses are ...

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

logic programming Logic programming is a programming, database and knowledge representation paradigm based on formal logic. A logic program is a set of sentences in logical form, representing knowledge about some problem domain. Computation is performed by applyin ...

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 Street (Manhattan), Canal to Houston Str ...

. 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 Boroughs of New York City, borough of New York City located at the westernmost end of Long Island in the New York (state), State of New York. Formerly an independent city, the borough is coextensive with Kings County, one of twelv ...

where Horn spent most of his childhood, raised by his extended family. Horn attended the

City College of New York The City College of the City University of New York (also known as the City College of New York, or simply City College or CCNY) is a Public university, public research university within the City University of New York (CUNY) system in New York ...

, and later,

New York University New York University (NYU) is a private university, private research university in New York City, New York, United States. Chartered in 1831 by the New York State Legislature, NYU was founded in 1832 by Albert Gallatin as a Nondenominational ...

where he earned a

Master's degree A master's degree (from Latin ) is a postgraduate 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 prac ...

mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

. He went on to earn his

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 ...

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

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 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 ...

, 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 the city of Los Angeles, California, situated about west of downtown Los Angeles. Throughout January 2025, the majority of Pacific Palisades was severely affected and destroyed by ...

after eight years of battling

prostate cancer Prostate cancer is the neoplasm, uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Abnormal growth of the prostate tissue is usually detected through Screening (medicine), screening tests, ...

References

Alfred Horn, Palisadian Since 1954 and Noted UCLA Math Professor
–

obituary An obituary (wikt:obit#Etymology 2, obit for short) is an Article (publishing), article about a recently death, deceased person. Newspapers often publish obituaries as Article (publishing), news articles. Although obituaries tend to focus on p ...

from UCLA
Publications of Alfred Horn
– a list compiled by Dimiter Skordev
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.. it contained information on 300,152 mathematical scientists who contributed to research-level mathematics. For a typical mathematicia ...

{{DEFAULTSORT:Horn, Alfred 1918 births 2001 deaths 20th-century American mathematicians American logicians Lattice theorists City College 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 Mathematicians from Brooklyn