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Definition df-nfOLD 1719
Description: Obsolete definition replaced by nf5 2114 as of 3-Oct-2021. This definition is less suitable than df-nf 1708 when ax-10 2017 and ax-12 2045 are not in effect. (Contributed by Mario Carneiro, 11-Aug-2016.) (New usage is discouraged.)
Assertion
Ref Expression
df-nfOLD (Ⅎ𝑥𝜑 ↔ ∀𝑥(𝜑 → ∀𝑥𝜑))

Detailed syntax breakdown of Definition df-nfOLD
StepHypRef Expression
1 wph . . 3 wff 𝜑
2 vx . . 3 setvar 𝑥
31, 2wnfOLD 1707 . 2 wff 𝑥𝜑
41, 2wal 1479 . . . 4 wff 𝑥𝜑
51, 4wi 4 . . 3 wff (𝜑 → ∀𝑥𝜑)
65, 2wal 1479 . 2 wff 𝑥(𝜑 → ∀𝑥𝜑)
73, 6wb 196 1 wff (Ⅎ𝑥𝜑 ↔ ∀𝑥(𝜑 → ∀𝑥𝜑))
Colors of variables: wff setvar class
This definition is referenced by:  nfiOLD  1732  nfbiiOLD  1834  nfdvOLD  1871  nfrOLD  2186  nfdOLD  2191  nfbidfOLD  2199  19.9dOLD  2201  nfnf1OLDOLD  2206  nfntOLD  2207  nfimdOLD  2224
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