Identifier
F:collatz-reaches-one
Proof route
Not assigned
External status
open
Axiom footprint
Empty

Recorded description

Iterating the map that halves an even number and sends an odd number m to 3m+1 reaches 1 from every positive starting value.

Formal statement
theorem Collatz.reaches_one : forall (n : Nat), 0 < n -> exists k : Nat, (fun m => if m % 2 = 0 then m / 2 else 3 * m + 1)^[k] n = 1

Dependencies

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0 direct dependencies 0 direct dependents

Evidence

Provenance

{
  "date": "2026-08-14",
  "established_by": "not established in this ledger",
  "source": "proposition extracted from the S:number strand of the math-education concept graph; statement authored here, nothing copied",
  "prior_art": [
    {
      "citation": "Collatz, circa 1937",
      "establishes": "the conjecture; still open"
    }
  ]
}