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Theorem a1iiOLD 28
Description: Obsolete proof of a1ii 27 as of 21-Jul-2019. Shorter proof, but uses one more axiom. (Contributed by Wolf Lammen, 23-Jul-2013.) (New usage is discouraged.) (Proof modification is discouraged.)
Ref Expression
Ref Expression

Proof of Theorem a1iiOLD
StepHypRef Expression
1 a1iiOLD.1 . . 3
21a1i 11 . 2
32a1d 25 1
Colors of variables: wff setvar class
Syntax hints:  ->wi 4
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7
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