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Common Neighbour Conjectures for Saxl Graphs

The paper disproves both the Burness–Giudici common neighbour conjecture for primitive groups of base size 22 and its later generalisation to arbitrary base size. For every integer B2B\ge2, it constructs infinitely many primitive permutation groups of base size BB whose generalised Saxl graphs contain two nonadjacent vertices with no common neighbour. At base size 22, it gives infinite counterexample families of affine, product and twisted wreath type, so the conjecture fails in three of the five O'Nan–Scott types.

Exact FrontierDelta

Prior state unknowndisproved

Scope and record

Occurred: Sep 1, 2026

Delta type: SOURCE CLAIM

Assumptions: VibeMathed verification: unreviewed. Publication: preprint. AI contribution: ai-co-developed. VibeMathed editorial classifications, scores, notes, relations, and dataset structure are CC BY 4.0. Source statements and linked content retain their own rights.

Canonical aliases: Common Neighbour Conjectures for Saxl Graphs · Saxl Common Neighbour

Confidence: Not scored

Registry verification: unreviewed · preprint · resolved

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Attribution

VibeMathed
registry · event recorded by

ChatGPT Pro
model · ai model contributor · OpenAI

Claude
model · ai model contributor · Anthropic

Aluna Rizzoli
human · human collaborator

Adam R. Thomas
human · human collaborator

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This event attributed to ChatGPT Pro

This event attributed to Aluna Rizzoli

VibeMathed record: Common Neighbour Conjectures for Saxl Graphs evidence for this event

This event attributed to Claude

This event attributed to Adam R. Thomas

Common Neighbour Conjectures for Saxl Graphs evidence for this event

The paper disproves both the Burness–Giudici common neighbour conjecture for primitive groups of base size 22 and its later generalisation to arbitrary base size. For every integer B2B\ge2, it constructs infinitely many primitive permutation groups of base size BB whose generalised Saxl graphs contain two nonadjacent vertices with no common neighbour. At base size 22, it gives infinite counterexample families of affine, product and twisted wreath type, so the conjecture fails in three of the five O'Nan–Scott types. parent of this event

Common Neighbour Conjectures for Saxl Graphs parent of this event

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