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Theorem

Brooks' Theorem

Combinatorics and Graph Theory

For a connected graph that is not a complete graph or an odd cycle, the chromatic number is at most equal to the maximum vertex degree. Proved by R. Leonard Brooks, it is a fundamental bound in graph coloring theory.

Facts
Statement
In a connected graph in which every vertex has degree at most delta, the vertices can be colored using only delta colors, except when the graph is a complete graph or an odd cycle, which require delta plus one colors. 2
Proof Year
1941 2
Classification
Statement Form
Inequality 1
Connections

Has Statement Form

Inequality, Concepts

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

Sources
1. Wikipedia: Brooks' theorem
WikipediaLead section, statement-form reference
Quote, Lead section, statement-form reference
According to the theorem, in a connected graph in which every vertex has at most Δ neighbors, the vertices can be colored with only Δ colors, except for two cases, complete graphs and cycle graphs of odd length, which require Δ + 1 colors.
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2. Brooks' Theorem (Wikipedia)
Wikimedia Foundation
  • Lead section
    in a connected graph in which every vertex has at most Δ neighbors, the vertices can be colored with only Δ colors, except for two cases, complete graphs and cycle graphs of odd length, which require Δ + 1 colors.
  • Lead section, proof year
    The theorem is named after R. Leonard Brooks, who published a proof of it in 1941.
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