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| Mirrors > Home > MPE Home > Th. List > Mathboxes > aifftbifffaibif | Structured version Visualization version GIF version | ||
| Description: Given a is equivalent to T., Given b is equivalent to F., there exists a proof for that a implies b is false. (Contributed by Jarvin Udandy, 7-Sep-2020.) |
| Ref | Expression |
|---|---|
| aifftbifffaibif.1 | ⊢ (𝜑 ↔ ⊤) |
| aifftbifffaibif.2 | ⊢ (𝜓 ↔ ⊥) |
| Ref | Expression |
|---|---|
| aifftbifffaibif | ⊢ ((𝜑 → 𝜓) ↔ ⊥) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | aifftbifffaibif.1 | . . . . 5 ⊢ (𝜑 ↔ ⊤) | |
| 2 | 1 | aistia 46851 | . . . 4 ⊢ 𝜑 |
| 3 | aifftbifffaibif.2 | . . . . 5 ⊢ (𝜓 ↔ ⊥) | |
| 4 | 3 | aisfina 46852 | . . . 4 ⊢ ¬ 𝜓 |
| 5 | 2, 4 | pm3.2i 470 | . . 3 ⊢ (𝜑 ∧ ¬ 𝜓) |
| 6 | annim 403 | . . . 4 ⊢ ((𝜑 ∧ ¬ 𝜓) ↔ ¬ (𝜑 → 𝜓)) | |
| 7 | 6 | biimpi 216 | . . 3 ⊢ ((𝜑 ∧ ¬ 𝜓) → ¬ (𝜑 → 𝜓)) |
| 8 | 5, 7 | ax-mp 5 | . 2 ⊢ ¬ (𝜑 → 𝜓) |
| 9 | 8 | bifal 1555 | 1 ⊢ ((𝜑 → 𝜓) ↔ ⊥) |
| Colors of variables: wff setvar class |
| Syntax hints: ¬ wn 3 → wi 4 ↔ wb 206 ∧ wa 395 ⊤wtru 1540 ⊥wfal 1551 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 |
| This theorem depends on definitions: df-bi 207 df-an 396 df-tru 1542 df-fal 1552 |
| This theorem is referenced by: atnaiana 46877 |
| Copyright terms: Public domain | W3C validator |