Syracuse descent for
Opensyracuse_descent_twentyseven_mod_thirtytwoLet be the Syracuse map. The assertion is that every has a finite accelerated stopping time:
This statement is open. It is the accelerated form of one of the three residue classes left open by the refinement of the Collatz descent problem modulo , and it implies its classical counterpart because the -orbit of an odd is a subsequence of its -orbit.
Each -step multiplies by with , so the accelerated map contracts on average while the classical map alternates growth and contraction; this is why the quantitative theory, from Terras's density theorem to Tao's almost-all result, is developed for .
Formalization Note. No positivity or oddness hypothesis is needed: forces and odd. The index is unconstrained, but can never witness the conclusion since is false.
import Mathlib import Definitions.Def_syracuseStep
theorem syracuse_descent_twentyseven_mod_thirtytwo (n : ℕ) (h : n % 32 = 27) :
∃ t : ℕ, syracuseStep^[t] n < n := by
sorry