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Description: A special case of sbequ1 . (Contributed by BJ, 22-Dec-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | bj-ssbid1 | ⊢ ( 𝜑 → [ 𝑥 / 𝑥 ] 𝜑 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | equid | ⊢ 𝑥 = 𝑥 | |
| 2 | sbequ1 | ⊢ ( 𝑥 = 𝑥 → ( 𝜑 → [ 𝑥 / 𝑥 ] 𝜑 ) ) | |
| 3 | 1 2 | ax-mp | ⊢ ( 𝜑 → [ 𝑥 / 𝑥 ] 𝜑 ) |