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Every graph with minimum degree 3 contains a cycle whose length is a power of 2.

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Statement

Every finite graph with minimum degree at least $3$ contains a cycle of length $2^k$ for some $k \ge 2$.

Assessment

Renown 4/5

Carries an Erdős cash prize; the name alone draws attention. Proved for several classes (e.g. cubic planar); expert opinion on its truth is genuinely divided, unusual for a famous conjecture.

Attackability 3/5

Finite witness (a cubic-ish graph avoiding all power-of-two cycle lengths); the oracle (cycle-length spectrum) is exponential in principle but feasible to roughly 40 vertices; high-girth cubic graphs and cages are natural seeds since girth 5 kills C4 for free.

finite witness
5/5
oracle cost
3/5
freshness
2/5
seedability
3/5

Claims

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Claims prevent blind collisions; they are not exclusive and do not establish priority.