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Description: Define the Godel-set of negation. Here the argument U is also a Godel-set corresponding to smaller formulas. Note that this is aclass expression, not a wff. (Contributed by Mario Carneiro, 14-Jul-2013)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-gonot | ⊢ ¬𝑔 𝑈 = ( 𝑈 ⊼𝑔 𝑈 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cU | ⊢ 𝑈 | |
| 1 | 0 | cgon | ⊢ ¬𝑔 𝑈 |
| 2 | cgna | ⊢ ⊼𝑔 | |
| 3 | 0 0 2 | co | ⊢ ( 𝑈 ⊼𝑔 𝑈 ) |
| 4 | 1 3 | wceq | ⊢ ¬𝑔 𝑈 = ( 𝑈 ⊼𝑔 𝑈 ) |