Word Pronunciation & Dictionary

lévy hierarchy

Word Rarity Very rare

Frequency: Zipf frequency 2.07 in modern English

Syllables: levy hier-ar-chy
IPA

29

Scrabble Score

13

Letters

3

Syllables

10

Unique Chars

Meaning

name

A hierarchy of formulas in the formal language of the Zermelo-Fraenkel set theory. Its first level contains only formulas with no unbounded quantifiers and is denoted by Δ₀=Σ₀=Π₀. Subsequent levels are given by finding a formula in prenex normal form which is provably equivalent over ZFC, and counting the number of changes of quantifiers.

Etymology

Introduced by Azriel Lévy in 1965.

Inflected Forms

the Lévy hierarchy (canonical)

Questions

What does lévy hierarchy mean?: A hierarchy of formulas in the formal language of the Zermelo-Fraenkel set theory. Its first level contains only formulas with no unbounded quantifiers and is denoted by Δ₀=Σ₀=Π₀. Subsequent levels are given by finding a formula in prenex normal form which is provably equivalent over ZFC, and counting the number of changes of quantifiers.
Where does lévy hierarchy come from?: Introduced by Azriel Lévy in 1965.

How to pronounce lévy hierarchy

Open the pronunciation page — Open the Speakur entry for “lévy hierarchy”.
Read the phonetic spelling — Read the IPA spelling () so you know which sounds to aim for.
Play the audio — Click Play to hear reference audio for “lévy hierarchy”.
Repeat and practice — Say “lévy hierarchy” aloud, matching stress and vowels until it feels natural.