Theorem bj-nnan 12953

Description: The double negation of a conjunction implies the conjunction of the double negations. (Contributed by BJ, 24-Nov-2023.)

Assertion

Ref	Expression
bj-nnan	⊢ (¬ ¬ (𝜑 ∧ 𝜓) → (¬ ¬ 𝜑 ∧ ¬ ¬ 𝜓))

Proof of Theorem bj-nnan

Step	Hyp	Ref	Expression
1		simpl 108	. . . 4 ⊢ ((𝜑 ∧ 𝜓) → 𝜑)
2	1	con3i 621	. . 3 ⊢ (¬ 𝜑 → ¬ (𝜑 ∧ 𝜓))
3	2	con3i 621	. 2 ⊢ (¬ ¬ (𝜑 ∧ 𝜓) → ¬ ¬ 𝜑)
4		simpr 109	. . . 4 ⊢ ((𝜑 ∧ 𝜓) → 𝜓)
5	4	con3i 621	. . 3 ⊢ (¬ 𝜓 → ¬ (𝜑 ∧ 𝜓))
6	5	con3i 621	. 2 ⊢ (¬ ¬ (𝜑 ∧ 𝜓) → ¬ ¬ 𝜓)
7	3, 6	jca 304	1 ⊢ (¬ ¬ (𝜑 ∧ 𝜓) → (¬ ¬ 𝜑 ∧ ¬ ¬ 𝜓))

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 103

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 603  ax-in2 604

This theorem is referenced by:  bj-stan  12960  bj-stand  12961