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Mirrors > Home > MPE Home > Th. List > nfanOLD | Structured version Visualization version GIF version |
Description: Obsolete proof of nfan 1828 as of 9-Oct-2021. (Contributed by Mario Carneiro, 11-Aug-2016.) (Proof shortened by Wolf Lammen, 13-Jan-2018.) (New usage is discouraged.) (Proof modification is discouraged.) |
Ref | Expression |
---|---|
nfan.1 | ⊢ Ⅎ𝑥𝜑 |
nfan.2 | ⊢ Ⅎ𝑥𝜓 |
Ref | Expression |
---|---|
nfanOLD | ⊢ Ⅎ𝑥(𝜑 ∧ 𝜓) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-an 386 | . 2 ⊢ ((𝜑 ∧ 𝜓) ↔ ¬ (𝜑 → ¬ 𝜓)) | |
2 | nfan.1 | . . . 4 ⊢ Ⅎ𝑥𝜑 | |
3 | nfan.2 | . . . . 5 ⊢ Ⅎ𝑥𝜓 | |
4 | 3 | nfn 1784 | . . . 4 ⊢ Ⅎ𝑥 ¬ 𝜓 |
5 | 2, 4 | nfim 1825 | . . 3 ⊢ Ⅎ𝑥(𝜑 → ¬ 𝜓) |
6 | 5 | nfn 1784 | . 2 ⊢ Ⅎ𝑥 ¬ (𝜑 → ¬ 𝜓) |
7 | 1, 6 | nfxfr 1779 | 1 ⊢ Ⅎ𝑥(𝜑 ∧ 𝜓) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 384 Ⅎwnf 1708 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-ex 1705 df-nf 1710 |
This theorem is referenced by: (None) |
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