Araujo-Piga-Schacht Question on Tight Hamilton Cycles
resolvedconfidence 70%
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Precise statement
Araujo, Piga and Schacht asked whether density and codegree both above $1/4$ force a tight Hamilton cycle in a linearly quasirandom 3-graph. No: the threshold is $p_0 = \max_{0 \le x \le 1}\min\{x^3, 1-x\} \approx 0.3177$, and below it there are dense 3-graphs with large codegree and no tight Hamilton cycle. For every $p > 1/3$ the asymptotically sharp minimum-codegree threshold is determined.
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