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
StatementThe maximum number of edges in a triangle-free graph on n vertices is the floor of n squared over four. 1 Classification
Statement Form Connections
Has Statement Form
Entity-backed identity for the statement-form enum value this theorem already carries, resolved to a mathematics concept by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The statement-form fact itself stays on the theorem unchanged.
In Branch
Source Turan's Theorem (Wikipedia)
Sources
1. Mantel's theorem - Wikipedia
Lead section
The maximum number of edges in an n-vertex triangle-free graph is floor of n squared over 4.
Lead section, second sentence
it was stated in 1907 by Willem Mantel, a Dutch mathematician.
View the SourceTuran's Theorem (Wikipedia)
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