English

The 3x+1 Problem: An Overview

Number Theory 2021-11-05 v1 Combinatorics History and Overview

Abstract

This paper is an overview and survey of work on the 3x+1 problem, also called the Collatz problem, and generalizations of it. It gives a history of the problem. It addresses two questions: (1) What can mathematics currently say about this problem? (as of 2010). (2) How can this problem be hard, when it is so easy to state?

Cite

@article{arxiv.2111.02635,
  title  = {The 3x+1 Problem: An Overview},
  author = {Jeffrey C. Lagarias},
  journal= {arXiv preprint arXiv:2111.02635},
  year   = {2021}
}

Comments

27 pages; page breaks and stylefile differ from published version; some typos corrected, journal references updated

R2 v1 2026-06-24T07:25:32.739Z