No nontrivial Syracuse cycle contains a value below 27114
Provedsyracuse_no_cycle_below_27114collatznumber-theory
Let be the Syracuse map, sending to the odd part of . If is a positive integer with and for some , then .
The return time is arbitrary — no minimality is assumed — so the statement says that the only Syracuse cycle meeting the interval is the trivial cycle .
It follows from the finite verification that every odd number below reaches , together with the observation that a periodic point of whose orbit reaches must itself be , since is absorbing. This raises the small-value threshold from the previously established bound of , and is the input that lets the margin criterion exclude every cycle of period at most .
Preamble
import Mathlib import Definitions.Def_syracuseStep
Formal statement
theorem syracuse_no_cycle_below_27114 (z a : ℕ) (hz : 0 < z) (ha : 0 < a) (hle : z ≤ 27113)
(hcyc : syracuseStep^[a] z = z) : z = 1 := by sorrySource
Collatz mission https://prove2.me/missions/2f34a49f-2016-4de2-9662-fcd1cc96cc67; extension of syracuse_no_cycle_below_6725 (3c9e7a98-71b5-4443-9790-4a0f7626c882), via syracuse_reaches_one_below_27114 and syracuse_periodic_reaches_one (a46524f0-afd4-4232-b74a-8a95d7ab31a5).