Minimum-degree Ramsey lower bound Created 2026-09-24 Updated 2026-09-24
If a graph has minimum degree , then its graph Ramsey number satisfies . The probabilistic proof chooses a red-blue edge colouring and applies the local lemma to its monochromatic copies of .
Past exam of the mathematics course of the University of Cambridge 2026 iii Paper 122 4 a Solution Created 2026-09-24 Updated 2026-09-24
The graph Ramsey number is the least such that every red-blue colouring of the edges of contains a monochromatic copy of .
The minimum-degree Ramsey lower bound states that a graph of minimum degree admits an -free colouring on every integer . Its probabilistic proof colours edges independently and applies the local lemma to the events that a labelled copy of is monochromatic. Sincethe exponential cost of a monochromatic copy dominates the number of compatible copies through every fixed edge. Hence such a colouring exists, and therefore