Sylvester-Gallai theorem

proper noun

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.

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Meanings

proper noun
  1. geometryA 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.

Origin

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.

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Cite this entry
APA

Sylvester-Gallai theorem. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/Sylvester-Gallai%20theorem

MLA

“Sylvester-Gallai theorem.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/Sylvester-Gallai%20theorem. Accessed November 5, 2026.

Chicago

WatkinsX Dictionary, s.v. “Sylvester-Gallai theorem,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/Sylvester-Gallai%20theorem.

Source: Sylvester-Gallai theorem on Wiktionary, CC BY-SA 4.0.