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Mantel's Theorem

Combinatorics and Graph Theory

Mantel's Theorem states that a triangle-free graph on n vertices has at most floor of n squared over four edges, a bound achieved exactly by the complete bipartite graph that splits the vertices into two halves as evenly as possible. Named for Willem Mantel, it is the earliest and simplest case of extremal graph theory's general study of how many edges a graph can have while avoiding a forbidden subgraph, later generalized by Turan's Theorem.

Facts
Statement
The maximum number of edges in a triangle-free graph on n vertices is the floor of n squared over four. 1
Proof Year
1907 1
Classification
Statement Form
Inequality 1
Connections

Has Statement Form

Inequality, Concepts

In Branch

Source Turan's Theorem (Wikipedia)
Sources
1. Mantel's theorem - Wikipedia
  • Lead section
    The special case of the theorem for triangle-free graphs is known as Mantel's theorem; it was stated in 1907 by Willem Mantel, a Dutch mathematician.
  • Lead section, second sentence
    it was stated in 1907 by Willem Mantel, a Dutch mathematician.
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Turan's Theorem (Wikipedia)
Wikimedia Foundation
  • In Group: Ramsey Theory and Extremal Combinatorics, Lead or opening section
    It is one of the central results of extremal graph theory, an area studying the largest or smallest graphs with given properties
  • In Branch: Graph Theory, Lead sentence
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