Two undecidable variants of Collatz's problems
The paper introduces a simple way to show that certain iterative, number theoretic problems are undecidable. As applications, variants of the Collatz's conjecture and the so-called Collatz's original problem are shown to be undecidable. (C) 2008 Elsevier B.V. All rights reserved.
undecidability collatz's conjecture collatz's original problem