Donald Solitar (September 5, 1932 in Brooklyn, New York, United States – April 28, 2008 in Toronto, Canada) was an American and Canadian mathematician, known for his work in combinatorial group theory.
Solitar competed on the mathematics team of Brooklyn Technical High School with his future co-author Abe Karrass, one year ahead of him in school.
However, his intended mentor there, Emil Artin, was no longer interested in group theory, so he left with a master's degree and earned his doctorate from New York University instead, in 1958, under the supervision of Wilhelm Magnus.
[1][2][3] After finishing his studies, he joined the faculty of Adelphi University in 1959, and Karrass soon joined him there as a doctoral student, earning a Ph.D. under Solitar's supervision in 1961; this was the first Ph.D. awarded at Adelphi.
Karrass remained on the faculty with Solitar, where they founded a summer institute for high school mathematics teachers.