English

Pan Galactic Division

Combinatorics 2015-04-13 v2

Abstract

This is a light expository article. It explains a proof, due to Peter Doyle and Cecil Qiu, the following result from set theory. Let A and B be sets. Suppose there is an injective map from A x {0,...,n-1} into B x {0,...,n-1}. Then there is an injection from A into B. Unlike previous proofs, this one is a very simple one.

Cite

@article{arxiv.1504.02179,
  title  = {Pan Galactic Division},
  author = {Richard Evan Schwartz},
  journal= {arXiv preprint arXiv:1504.02179},
  year   = {2015}
}

Comments

5 pages; this will eventually appear as an Intelligencer article. This is a replacement of yesterday's submission, and differs only in that I changed the abstract

R2 v1 2026-06-22T09:13:13.344Z