This proof demonstrates the only cycle in the Collatz sequence is trivial, implying no nontrivial cycles exist.
We prove that the only cycle in the Collatz sequence (the 3n+1 problem) is the trivial cycle 1 → 4 → 2 → 1. The proof combines algebraic reduction to a Diophantine equation, numerical verification up to a computable boundary, and asymptotic analysis beyond that boundary. This result establishes that nontrivial cycles in the Collatz conjecture are impossible.
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Vitaly Reznik (2026) studied this question.
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