Theorem zeo4 14900

Description: An integer is even or odd but not both. With this representation of even and odd integers, this variant of zeo2 11340 follows immediatly from the principle of double negation, see notnotb 303. (Contributed by AV, 17-Jun-2021.)

Assertion

Ref	Expression
zeo4	⊢ (𝑁 ∈ ℤ → (2 ∥ 𝑁 ↔ ¬ ¬ 2 ∥ 𝑁))

Proof of Theorem zeo4

Step	Hyp	Ref	Expression
1		notnotb 303	. 2 ⊢ (2 ∥ 𝑁 ↔ ¬ ¬ 2 ∥ 𝑁)
2	1	a1i 11	1 ⊢ (𝑁 ∈ ℤ → (2 ∥ 𝑁 ↔ ¬ ¬ 2 ∥ 𝑁))

Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 195   ∈ wcel 1977   class class class wbr 4583  2c2 10947  ℤcz 11254   ∥ cdvds 14821

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 196

This theorem is referenced by: (None)