This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Description: Distribute substitution over implication. (Contributed by NM, 25-Jun-1998) Revise df-sb . (Revised by BJ, 22-Dec-2020) (Proof shortened by Steven Nguyen, 24-Jul-2023)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | sbimi.1 | ⊢ ( 𝜑 → 𝜓 ) | |
| Assertion | sbimi | ⊢ ( [ 𝑡 / 𝑥 ] 𝜑 → [ 𝑡 / 𝑥 ] 𝜓 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sbimi.1 | ⊢ ( 𝜑 → 𝜓 ) | |
| 2 | 1 | sbt | ⊢ [ 𝑡 / 𝑥 ] ( 𝜑 → 𝜓 ) |
| 3 | sbi1 | ⊢ ( [ 𝑡 / 𝑥 ] ( 𝜑 → 𝜓 ) → ( [ 𝑡 / 𝑥 ] 𝜑 → [ 𝑡 / 𝑥 ] 𝜓 ) ) | |
| 4 | 2 3 | ax-mp | ⊢ ( [ 𝑡 / 𝑥 ] 𝜑 → [ 𝑡 / 𝑥 ] 𝜓 ) |