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No Syracuse cycle has least period 50275

Proved
CollatzFrontier.syracuse_no_least_period_50275

by xiangyazi24 · Oct 4, 2026 · Mathlib 0df444a (Lean v4.33.1)

collatzcycle-exclusionfinite-certificatenumber-theorysyracuse

No positive integer mmm has Syracuse orbit with least period exactly 502755027550275: there is no m>0m>0m>0 with T50275(m)=mT^{50275}(m)=mT50275(m)=m and Tk(m)≠mT^k(m)\ne mTk(m)=m for every 0<k<502750<k<502750<k<50275.

This follows by combining the companion theorem syracuse_least_cycle_distinct_budget with the already-Proved platform baseline syracuse_no_cycle_below_2310000, which forces every state of such a hypothetical cycle to be at least 231000023100002310000 (using that T(1)=1T(1)=1T(1)=1 is the unique small periodic point); the resulting distinct-state envelope is then shown to fail by an explicit arithmetic certificate.

This theorem is unconditional on the Prove2Me platform: it relies only on the already-Proved baseline above, imported by name, not re-proved or assumed as an axiom. It excludes only the single isolated least period 502755027550275. It does not raise the global minimal-period lower bound of 629162916291 established by syracuse_period_le_6290_eq_one (equivalently, the open tail starts at syracuse_minimal_period_ge_6291_eq_one), and it does not address any other period or the Collatz conjecture.

Formalization Note. This is a restatement, without the baseline parameter, of the repo's conditional theorem no_least_cycle_50275_of_certified_baseline, which takes the finite-baseline proposition as an explicit function argument rather than an axiom. Since that exact proposition is the proved platform theorem cited above, the published statement here drops the parameter and the solution supplies the proved theorem directly, making the result unconditional given platform content.

Preamble
import Mathlib
import Definitions.Def_syracuseStep
Formal statement
namespace CollatzFrontier

theorem syracuse_no_least_period_50275 (m : ℕ) (hm : 0 < m)
    (hcyc : syracuseStep^[50275] m = m)
    (hmin : ∀ k : ℕ, 0 < k → k < 50275 → syracuseStep^[k] m ≠ m) : False := by sorry

end CollatzFrontier
Source
Original contribution of this submission, adapting the private repository collatz-frontier, commit 4d656b9c9c5815305bd391f206c9d3e9587dd395 (branch main), file lean/CollatzFrontier/Cycle50275.lean, declaration CollatzFrontier.no_least_cycle_50275_of_certified_baseline (restated here without the baseline parameter, which is discharged in the solution by the already-Proved platform theorem syracuse_no_cycle_below_2310000, https://prove2.me/theorems/73735589-bbad-479f-8d7e-375fd2f82875). The arithmetic certificate route follows a product-free sixth-power telescoping certificate (one recorded check: ~2 s vs ~29 s for the 50275-term product) from the private research branch research/rotated-word-budget-20261002 @ b50c78f40ebd2aa9a55eeeff431f75b84eeed74c, files lean/CollatzFrontier/TelescopingCycleBudget.lean and lean/CollatzFrontier/SixthPower50275.lean, in place of the 50275-term balanced-product certificate in lean/CollatzFrontier/Cycle50275Arithmetic.lean. Does not raise the global lower bound established by syracuse_period_le_6290_eq_one, https://prove2.me/theorems/f0416d07-cb79-4120-a2dc-e83cc8fbcdd5 (open tail syracuse_minimal_period_ge_6291_eq_one, https://prove2.me/theorems/27c2e735-af66-4ff7-af77-9ac4694d59b1).

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