The story
Named after James Joseph Sylvester, who posed it as a problem in 1893, and Tibor Gallai, who published one of the first proofs of this theorem in 1944.
Etymology from Wiktionary, CC BY-SA 4.0.
Sylvester-Gallai theorem
Today it means: A theorem stating that, given a finite number of points in the Euclidean plane, either all the points lie on a single line, or there is at least one line which contains exactly two of the points. Full definition →