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Description: Restricted existential specialization, using implicit substitution. Variant of rspcedvd for equations, in which the left hand side depends on the quantified variable. (Contributed by AV, 24-Dec-2019)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | rspcedeqvd.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝐵 ) | |
| rspcedeqvd.2 | ⊢ ( ( 𝜑 ∧ 𝑥 = 𝐴 ) → 𝐶 = 𝐷 ) | ||
| Assertion | rspcedeq1vd | ⊢ ( 𝜑 → ∃ 𝑥 ∈ 𝐵 𝐶 = 𝐷 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | rspcedeqvd.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝐵 ) | |
| 2 | rspcedeqvd.2 | ⊢ ( ( 𝜑 ∧ 𝑥 = 𝐴 ) → 𝐶 = 𝐷 ) | |
| 3 | 2 | eqeq1d | ⊢ ( ( 𝜑 ∧ 𝑥 = 𝐴 ) → ( 𝐶 = 𝐷 ↔ 𝐷 = 𝐷 ) ) |
| 4 | eqidd | ⊢ ( 𝜑 → 𝐷 = 𝐷 ) | |
| 5 | 1 3 4 | rspcedvd | ⊢ ( 𝜑 → ∃ 𝑥 ∈ 𝐵 𝐶 = 𝐷 ) |