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Related theorems GIF version |
| Description: Class identity law (reflexivity of class equality). Theorem 6.4 of [Quine] p. 41. |
| Ref | Expression |
|---|---|
| eqid | ⊢ A = A |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pm4.2 170 | . 2 ⊢ (x ∈ A ↔ x ∈ A) | |
| 2 | 1 | eqriv 1472 | 1 ⊢ A = A |