name | natural-min-max-def |
version | 1.3 |
description | natural-min-max-def |
author | Joe Hurd <joe@gilith.com> |
license | HOLLight |
provenance | HOL Light theory extracted on 2011-07-20 |
show | Data.Bool |
⊦ ∀m n. Number.Natural.max m n = if Number.Natural.≤ m n then n else m
⊦ ∀m n. Number.Natural.min m n = if Number.Natural.≤ m n then m else n
⊦ ∀P.
(∃n. P n) ⇔
P (Number.Natural.minimal P) ∧
∀m. Number.Natural.< m (Number.Natural.minimal P) ⇒ ¬P m
⊦ T
⊦ (∃) = λP. P ((select) P)
⊦ (∀) = λp. p = λx. T
⊦ ∀x. x = x ⇔ T
⊦ (⇒) = λp q. p ∧ q ⇔ p
⊦ (∧) = λp q. (λf. f p q) = λf. f T T
⊦ ∀P. (∃n. P n) ⇔ ∃n. P n ∧ ∀m. Number.Natural.< m n ⇒ ¬P m