Theorem 2a1 25

Description: A double form of ax-1 6. Its associated inference is 2a1i 27. Its associated deduction is 2a1d 23. (Contributed by BJ, 10-Aug-2020.) (Proof shortened by Wolf Lammen, 1-Sep-2020.)

Assertion

Ref	Expression
2a1	⊢ (𝜑 → (𝜓 → (𝜒 → 𝜑)))

Proof of Theorem 2a1

Step	Hyp	Ref	Expression
1		id 19	. 2 ⊢ (𝜑 → 𝜑)
2	1	2a1d 23	1 ⊢ (𝜑 → (𝜓 → (𝜒 → 𝜑)))

Syntax hints:   → wi 4

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

This theorem is referenced by:  xnn0lenn0nn0  9641  dfgcd2  11691