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Description: A Virtual deduction elimination rule. syl is el1 without virtual deductions. (Contributed by Alan Sare, 23-Apr-2015) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | el1.1 | ⊢ ( 𝜑 ▶ 𝜓 ) | |
| el1.2 | ⊢ ( 𝜓 → 𝜒 ) | ||
| Assertion | el1 | ⊢ ( 𝜑 ▶ 𝜒 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | el1.1 | ⊢ ( 𝜑 ▶ 𝜓 ) | |
| 2 | el1.2 | ⊢ ( 𝜓 → 𝜒 ) | |
| 3 | 1 | in1 | ⊢ ( 𝜑 → 𝜓 ) |
| 4 | 3 2 | syl | ⊢ ( 𝜑 → 𝜒 ) |
| 5 | 4 | dfvd1ir | ⊢ ( 𝜑 ▶ 𝜒 ) |