/- Copyright 2026 The Formal Conjectures Authors. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at https://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -/ import FormalConjectures.Wikipedia.CollatzConjecture

Erdős Problem 1135

The Collatz conjecture states that for any positive integer $n$, there exists a natural number $m$ such that the $m$-th term of the sequence is 1.

References:

    erdosproblems.com/1135

    [Gu04] Guy, Richard K., Unsolved problems in number theory. (2004), xviii+437.

    [La10] Lagarias, Jeffrey C., The {$3x+1$} problem: an overview. (2010), 3--29.

    [La16] Lagarias, Jeffrey C., Erdős, Klarner, and the {$3x+1$} problem. Amer. Math. Monthly (2016), 753--776.

    [La85] Lagarias, Jeffrey C., The {$3x+1$} problem and its generalizations. Amer. Math. Monthly (1985), 3--23.

This file points to the canonical formalization in FormalConjectures.Wikipedia.CollatzConjecture.

namespace Erdos1135

The Collatz conjecture states that for any positive integer $n$, there exists a natural number $m$ such that the $m$-th term of the sequence is 1.

@[category research open, AMS 11 37] theorem declaration uses 'sorry'erdos_1135 : type_of% CollatzConjecture.collatz_conjecture := n > 0, m, CollatzConjecture.collatzStep^[m] n = 1 All goals completed! 🐙 end Erdos1135