# Minkowski's question mark function

> English word · Proper noun

## Definitions
1. A function, denoted ?(x), with unusual fractal properties, mapping quadratic irrational numbers to rational numbers on the unit interval, via an expression relating the continued fraction expansions of the quadratics to the binary expansions of the rationals.

## Etymology
Defined by Hermann Minkowski in 1904.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/minkowski-s-question-mark-function