Lévy hierarchy en · PROPN
Etymology
Introduced by Azriel Lévy in 1965.
Meanings
- 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.
Forms
| Spelling | Features | Labels | Source |
|---|---|---|---|
| the Lévy hierarchy | canonical | lexicographic |