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Axiom ax-10o 2139
 Description: Axiom ax-10o 2139 ("o" for "old") was the original version of ax-10 2140, before it was discovered (in May 2008) that the shorter ax-10 2140 could replace it. It appears as Axiom scheme C11' in [Megill] p. 448 (p. 16 of the preprint). This axiom is obsolete and should no longer be used. It is proved above as theorem ax10o 1952. (Contributed by NM, 5-Aug-1993.) (New usage is discouraged.)
Assertion
Ref Expression
ax-10o (x x = y → (xφyφ))

Detailed syntax breakdown of Axiom ax-10o
StepHypRef Expression
1 vx . . . 4 setvar x
2 vy . . . 4 setvar y
31, 2weq 1643 . . 3 wff x = y
43, 1wal 1540 . 2 wff x x = y
5 wph . . . 4 wff φ
65, 1wal 1540 . . 3 wff xφ
75, 2wal 1540 . . 3 wff yφ
86, 7wi 4 . 2 wff (xφyφ)
94, 8wi 4 1 wff (x x = y → (xφyφ))
 Colors of variables: wff setvar class This axiom is referenced by:  aecom-o  2151  hbae-o  2153  dral1-o  2154  ax10from10o  2177  dvelimf-o  2180
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