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| Mirrors > Home > ILE Home > Th. List > elrab2 | GIF version | ||
| Description: Membership in a class abstraction, using implicit substitution. (Contributed by NM, 2-Nov-2006.) | 
| Ref | Expression | 
|---|---|
| elrab2.1 | ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) | 
| elrab2.2 | ⊢ 𝐶 = {𝑥 ∈ 𝐵 ∣ 𝜑} | 
| Ref | Expression | 
|---|---|
| elrab2 | ⊢ (𝐴 ∈ 𝐶 ↔ (𝐴 ∈ 𝐵 ∧ 𝜓)) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | elrab2.2 | . . 3 ⊢ 𝐶 = {𝑥 ∈ 𝐵 ∣ 𝜑} | |
| 2 | 1 | eleq2i 2263 | . 2 ⊢ (𝐴 ∈ 𝐶 ↔ 𝐴 ∈ {𝑥 ∈ 𝐵 ∣ 𝜑}) | 
| 3 | elrab2.1 | . . 3 ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) | |
| 4 | 3 | elrab 2920 | . 2 ⊢ (𝐴 ∈ {𝑥 ∈ 𝐵 ∣ 𝜑} ↔ (𝐴 ∈ 𝐵 ∧ 𝜓)) | 
| 5 | 2, 4 | bitri 184 | 1 ⊢ (𝐴 ∈ 𝐶 ↔ (𝐴 ∈ 𝐵 ∧ 𝜓)) | 
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