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	|- ( ph -> ( ps -> ( ch -> ph ) ) )

Proof of Theorem 2a1

Step	Hyp	Ref	Expression
1		id 19	. 2 |- ( ph -> ph )
2	1	2a1d 23	1 |- ( ph -> ( ps -> ( ch -> ph ) ) )

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  9861  dfgcd2  12007