October 1996 marked the launch of Cut-the-Knot, an interactive educational platform that became a cornerstone of internet-based mathematics communication. Created by Alexander Bogomolny, the site curated hundreds of problems and proofs, ranging from classic geometric theorems to complex probability riddles, establishing a digital repository designed to cultivate public curiosity and appreciation for the mathematical arts.
Academic Foundation
Born in Moscow in 1948, Bogomolny attended School No. 444 before enrolling at Lomonosov Moscow State University, where he completed his master's degree in 1971. His early professional career included a junior research fellowship at the Moscow Institute of Electronic Machine Building. Following his emigration to Israel, he served as a senior programmer at the Lake Kinneret Research Laboratory in Tiberias from 1974 to 1977. He earned his Ph.D. at the Hebrew University of Jerusalem in 1981, writing a dissertation titled A New Numerical Solution for the Stamp Problem under the supervision of Gregory I. Eskin.
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Bogomolny held several academic positions throughout his career. Between 1976 and 1983, he worked as a senior instructor and researcher at the Hebrew University of Jerusalem. His tenure included a term as a visiting professor at Ohio State University during the 1981–1982 academic year. From 1982 to 1987, he served as a professor of mathematics at the University of Iowa. He later transitioned into the software industry, notably serving as vice president of software development at CompuDoc, Inc. from 1987 to 1991.
Development of Cut-the-Knot
The Cut-the-Knot website functioned as an advertisement-funded resource for students, teachers, and enthusiasts until his death in 2018. The platform utilized Java applets and later GeoGebra applications to provide interactive visual proofs for subjects such as arithmetic, trigonometry, and algebra. It featured extensive analyses of topics including Napoleon's theorem and the Apollonian gasket, alongside a famous compilation of 122 distinct proofs for the Pythagorean theorem. The project earned recognition from publications including Scientific American and Encyclopædia Britannica.
Later Years and Legacy
Bogomolny contended with a significant hearing impairment that eventually influenced his departure from traditional academic roles. After his death in New Brunswick in 2018 at the age of 70, his work continued to influence the field through posthumous publications. In 2020, Wolfram Media released Cut the Knot: Probability Riddles, a collection curated from his website material. His legacy is also marked by a series of personal reflections written by his son, David, concerning the experience of mourning.
Fast facts
- Born: 1948, Moscow
- Died: 2018, New Brunswick
- Education: Lomonosov Moscow State University, Hebrew University of Jerusalem
- Ph.D. Dissertation: A New Numerical Solution for the Stamp Problem
- Website launched: October 1996
- Field: Mathematics
- Key Post: Professor of Mathematics, University of Iowa (1982-1987)
Questions readers ask
What was the purpose of the Cut-the-Knot website?
It served as a free, interactive educational resource designed to encourage curiosity and demonstrate the aesthetic beauty of mathematics to students, teachers, and parents.
Why did Bogomolny leave academic positions?
He eventually stepped away from academia due to a chronic, uncorrectable hearing problem.
Achievements
- Held posts at University of Iowa, Hebrew University of Jerusalem and Ben-Gurion University of the Negev
