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Mirrors > Home > ILE Home > Th. List > pm3.2ni | GIF version |
Description: Infer negated disjunction of negated premises. (Contributed by NM, 4-Apr-1995.) |
Ref | Expression |
---|---|
pm3.2ni.1 | ⊢ ¬ 𝜑 |
pm3.2ni.2 | ⊢ ¬ 𝜓 |
Ref | Expression |
---|---|
pm3.2ni | ⊢ ¬ (𝜑 ∨ 𝜓) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm3.2ni.1 | . 2 ⊢ ¬ 𝜑 | |
2 | id 19 | . . 3 ⊢ (𝜑 → 𝜑) | |
3 | pm3.2ni.2 | . . . 4 ⊢ ¬ 𝜓 | |
4 | 3 | pm2.21i 607 | . . 3 ⊢ (𝜓 → 𝜑) |
5 | 2, 4 | jaoi 668 | . 2 ⊢ ((𝜑 ∨ 𝜓) → 𝜑) |
6 | 1, 5 | mto 620 | 1 ⊢ ¬ (𝜑 ∨ 𝜓) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 ∨ wo 661 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-ia2 105 ax-ia3 106 ax-in1 576 ax-in2 577 ax-io 662 |
This theorem depends on definitions: df-bi 115 |
This theorem is referenced by: xrltnr 8855 pnfnlt 8862 nltmnf 8863 |
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