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Mirrors > Home > MPE Home > Th. List > nfxfrOLD | Structured version Visualization version GIF version |
Description: Obsolete proof of nfxfr 1771 as of 6-Oct-2021. (Contributed by Mario Carneiro, 11-Aug-2016.) (Proof modification is discouraged.) (New usage is discouraged.) |
Ref | Expression |
---|---|
nfbiiOLD.1 | ⊢ (𝜑 ↔ 𝜓) |
nfxfrOLD.2 | ⊢ Ⅎ𝑥𝜓 |
Ref | Expression |
---|---|
nfxfrOLD | ⊢ Ⅎ𝑥𝜑 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nfxfrOLD.2 | . 2 ⊢ Ⅎ𝑥𝜓 | |
2 | nfbiiOLD.1 | . . 3 ⊢ (𝜑 ↔ 𝜓) | |
3 | 2 | nfbiiOLD 1824 | . 2 ⊢ (Ⅎ𝑥𝜑 ↔ Ⅎ𝑥𝜓) |
4 | 1, 3 | mpbir 220 | 1 ⊢ Ⅎ𝑥𝜑 |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 195 ℲwnfOLD 1700 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 |
This theorem depends on definitions: df-bi 196 df-nfOLD 1712 |
This theorem is referenced by: nfnf1OLDOLD 2196 nfnanOLD 2226 nf3anOLD 2227 nforOLD 2232 nf3orOLD 2233 |
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