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| Mirrors > Home > MPE Home > Th. List > Mathboxes > aiffnbandciffatnotciffb | Structured version Visualization version GIF version | ||
| Description: Given a is equivalent to (not b), c is equivalent to a, there exists a proof for ( not ( c iff b ) ). (Contributed by Jarvin Udandy, 7-Sep-2016.) | 
| Ref | Expression | 
|---|---|
| aiffnbandciffatnotciffb.1 | ⊢ (𝜑 ↔ ¬ 𝜓) | 
| aiffnbandciffatnotciffb.2 | ⊢ (𝜒 ↔ 𝜑) | 
| Ref | Expression | 
|---|---|
| aiffnbandciffatnotciffb | ⊢ ¬ (𝜒 ↔ 𝜓) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | aiffnbandciffatnotciffb.2 | . . 3 ⊢ (𝜒 ↔ 𝜑) | |
| 2 | aiffnbandciffatnotciffb.1 | . . 3 ⊢ (𝜑 ↔ ¬ 𝜓) | |
| 3 | 1, 2 | bitri 275 | . 2 ⊢ (𝜒 ↔ ¬ 𝜓) | 
| 4 | xor3 382 | . 2 ⊢ (¬ (𝜒 ↔ 𝜓) ↔ (𝜒 ↔ ¬ 𝜓)) | |
| 5 | 3, 4 | mpbir 231 | 1 ⊢ ¬ (𝜒 ↔ 𝜓) | 
| Colors of variables: wff setvar class | 
| Syntax hints: ¬ wn 3 ↔ wb 206 | 
| 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 | 
| This theorem is referenced by: axorbciffatcxorb 46917 | 
| Copyright terms: Public domain | W3C validator |