English

A formula for any real number, maybe

Logic 2026-02-03 v1 History and Overview

Abstract

We discuss how to write down three specific natural numbers AA, BB, CC such that for any real number rr you've probably ever thought of, it is consistent with ZFC\mathsf{ZFC} set theory that r=log(supx0,x1Rinfx2Rsupx3Rinfx4RsupmNinfn0,,nANx02[+(n02)2+(n1m)2+n2+(nBnC)2+n3k=04(xknk+51+n4+n4)2+i,j=0B(n9+2i3jninj)2]).\def\Rb{\mathbb{R}}\def\Nb{\mathbb{N}}r = \log\left(\sup_{x_0,x_1 \in \Rb} \inf_{x_2 \in \Rb} \sup_{x_3 \in \Rb}\inf_{x_4 \in \Rb}\sup_{m \in \Nb}\inf_{n_0,\dots,n_{A} \in \Nb} x^2_0 \begin{bmatrix} \phantom{+}(n_0 - 2)^2 + (n_1-m)^2 \\ + n_2 + (n_B - n_C)^2 \\ + n_3 \sum_{k=0}^4 ( x_k - \frac{n_{k+5}}{1+n_4} +n_4)^2 \\ + \sum_{i,j = 0}^B (n_{9+2^i3^j} - n_i^{n_j})^2 \end{bmatrix} \right). We also discuss why it's possible, assuming the existence of certain large cardinals, for there to be a real number ss which cannot be the value of this formula for our particular AA, BB, CC. This involves set-theoretic mice.

Keywords

Cite

@article{arxiv.2602.02384,
  title  = {A formula for any real number, maybe},
  author = {James E. Hanson and Connor Watson},
  journal= {arXiv preprint arXiv:2602.02384},
  year   = {2026}
}

Comments

17 pages, 3 figures

R2 v1 2026-07-01T09:32:23.504Z