# von Neumann's inequality

> English word · Proper noun

## Definitions
1. In operator theory, the statement that, for a fixed contraction T, the polynomial functional calculus map is itself a contraction.

## Etymology
Due to John von Neumann.

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