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Mirrors > Home > MPE Home > Th. List > r19.35OLD | Structured version Visualization version GIF version |
Description: Obsolete version of 19.35 1872 as of 22-Dec-2024. (Contributed by NM, 20-Sep-2003.) (Proof modification is discouraged.) (New usage is discouraged.) |
Ref | Expression |
---|---|
r19.35OLD | ⊢ (∃𝑥 ∈ 𝐴 (𝜑 → 𝜓) ↔ (∀𝑥 ∈ 𝐴 𝜑 → ∃𝑥 ∈ 𝐴 𝜓)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rexim 3079 | . . 3 ⊢ (∀𝑥 ∈ 𝐴 ((𝜑 → 𝜓) → 𝜓) → (∃𝑥 ∈ 𝐴 (𝜑 → 𝜓) → ∃𝑥 ∈ 𝐴 𝜓)) | |
2 | pm2.27 42 | . . . 4 ⊢ (𝜑 → ((𝜑 → 𝜓) → 𝜓)) | |
3 | 2 | ralimi 3075 | . . 3 ⊢ (∀𝑥 ∈ 𝐴 𝜑 → ∀𝑥 ∈ 𝐴 ((𝜑 → 𝜓) → 𝜓)) |
4 | 1, 3 | syl11 33 | . 2 ⊢ (∃𝑥 ∈ 𝐴 (𝜑 → 𝜓) → (∀𝑥 ∈ 𝐴 𝜑 → ∃𝑥 ∈ 𝐴 𝜓)) |
5 | rexnal 3092 | . . . 4 ⊢ (∃𝑥 ∈ 𝐴 ¬ 𝜑 ↔ ¬ ∀𝑥 ∈ 𝐴 𝜑) | |
6 | pm2.21 123 | . . . . 5 ⊢ (¬ 𝜑 → (𝜑 → 𝜓)) | |
7 | 6 | reximi 3076 | . . . 4 ⊢ (∃𝑥 ∈ 𝐴 ¬ 𝜑 → ∃𝑥 ∈ 𝐴 (𝜑 → 𝜓)) |
8 | 5, 7 | sylbir 234 | . . 3 ⊢ (¬ ∀𝑥 ∈ 𝐴 𝜑 → ∃𝑥 ∈ 𝐴 (𝜑 → 𝜓)) |
9 | ax-1 6 | . . . 4 ⊢ (𝜓 → (𝜑 → 𝜓)) | |
10 | 9 | reximi 3076 | . . 3 ⊢ (∃𝑥 ∈ 𝐴 𝜓 → ∃𝑥 ∈ 𝐴 (𝜑 → 𝜓)) |
11 | 8, 10 | ja 186 | . 2 ⊢ ((∀𝑥 ∈ 𝐴 𝜑 → ∃𝑥 ∈ 𝐴 𝜓) → ∃𝑥 ∈ 𝐴 (𝜑 → 𝜓)) |
12 | 4, 11 | impbii 208 | 1 ⊢ (∃𝑥 ∈ 𝐴 (𝜑 → 𝜓) ↔ (∀𝑥 ∈ 𝐴 𝜑 → ∃𝑥 ∈ 𝐴 𝜓)) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 ∀wral 3053 ∃wrex 3062 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 |
This theorem depends on definitions: df-bi 206 df-an 396 df-ex 1774 df-ral 3054 df-rex 3063 |
This theorem is referenced by: (None) |
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