Mathematics Atlas

How Proof Is Made
Sign In
Text size
100%
Theme
Theorem

Sylvester-Gallai Theorem

Geometry

The Sylvester-Gallai Theorem states that given a finite set of points in the plane that are not all collinear, there always exists a line passing through exactly two of them. First posed as a problem by James Joseph Sylvester and later proved by Tibor Gallai, it is a foundational result in combinatorial geometry.

Facts
Statement
The Sylvester-Gallai theorem in geometry states that every finite set of points in the Euclidean plane has a line that passes through exactly two of the points or a line that passes through all of them. 1
Proof Year
1944 1
Classification
Statement Form
Existence Theorem 1
Connections

Has Statement Form

In Branch

Proved By

Source Sylvester-Gallai Theorem (Wikipedia)
Sources
1. Sylvester-Gallai Theorem (Wikipedia)
Wikimedia Foundation
  • Lead paragraph, first sentence
    The Sylvester-Gallai theorem in geometry states that every finite set of points in the Euclidean plane has a line that passes through exactly two of the points or a line that passes through all of them.
  • Lead paragraph, naming sentence
    It is 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.
  • Proved By: Tibor Gallai, Lead
    Unaware of Melchior's proof, Paul Erdős (1943) again stated the conjecture, which was subsequently proved by Tibor Gallai, and soon afterwards by other authors.
View the Source
Comments (0)
No comments yet. Be the first to share a thought.
Reader Challenges (0)
No disputes yet. Spotted an error or a better source? Open the first one.