Skip to content
← Hall of Internet Greatness
Featured Math & Formalism

RIES — Robert Munafo's Inverse Equation Solver

One of the internet's great mathematical tools: type a number, get the simple expressions that might explain it.

The Order of Inverse Sorcery

For creating a program that feels impossible, useful, and slightly illegal.

Why It Belongs

RIES is a command-line program that takes a real number and searches for simple algebraic expressions that might explain it. Give it 2.506628 and it can tell you that the number is approximately √(2π), which is exactly the kind of output that makes the tool feel slightly impossible.

It belongs in the Hall because it compresses a deep mathematical trick into an interface so direct that it feels illicit. The RIES documentation page alone is worth reading as a tutorial on inverse equation solving, expression enumeration, and computational number theory.

What To Preserve

Preserve both the program and the explanatory material around it.

What matters here is not just that the binary exists. The documentation, examples, and surrounding mathematical exposition are part of the artifact, and they are why I liked it enough to rewrite it in Rust.

Related Inductees

Adjacent artifacts, tools, and internet relics

Back to the full Hall →

The Iron Formalist Medal

For proving that a theorem prover can also be a serious programming language.

Math & Formalism

Lean 4

Functional programming language and interactive theorem prover. The best current tool for formal mathematics that is also a real programming language.

The Order of Mathematical Public Service

For making it possible to look at a strange sequence of integers and ask the internet what universe it belongs to.

Featured Research & Reference

OEIS — The On-Line Encyclopedia of Integer Sequences

A monumental reference work for integer sequences: part encyclopedia, part mathematical commons, part search engine for pattern recognition.