Mathbox for Norm Megill |
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Mirrors > Home > MPE Home > Th. List > Mathboxes > nfcxfrdf | Structured version Visualization version GIF version |
Description: A utility lemma to transfer a bound-variable hypothesis builder into a definition. (Contributed by NM, 19-Nov-2020.) |
Ref | Expression |
---|---|
nfcxfrdf.0 | ⊢ Ⅎ𝑥𝜑 |
nfcxfrdf.1 | ⊢ (𝜑 → 𝐴 = 𝐵) |
nfcxfrdf.2 | ⊢ (𝜑 → Ⅎ𝑥𝐵) |
Ref | Expression |
---|---|
nfcxfrdf | ⊢ (𝜑 → Ⅎ𝑥𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nfcxfrdf.2 | . 2 ⊢ (𝜑 → Ⅎ𝑥𝐵) | |
2 | nfcxfrdf.0 | . . 3 ⊢ Ⅎ𝑥𝜑 | |
3 | nfcxfrdf.1 | . . 3 ⊢ (𝜑 → 𝐴 = 𝐵) | |
4 | 2, 3 | nfceqdf 2974 | . 2 ⊢ (𝜑 → (Ⅎ𝑥𝐴 ↔ Ⅎ𝑥𝐵)) |
5 | 1, 4 | mpbird 259 | 1 ⊢ (𝜑 → Ⅎ𝑥𝐴) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1537 Ⅎwnf 1784 Ⅎwnfc 2963 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2116 ax-9 2124 ax-12 2177 ax-ext 2795 |
This theorem depends on definitions: df-bi 209 df-an 399 df-ex 1781 df-nf 1785 df-cleq 2816 df-clel 2895 df-nfc 2965 |
This theorem is referenced by: (None) |
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