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Description: Membership in a power class. Theorem 86 of Suppes p. 47. Derived from elpwg . In form of VD deduction with ph and ps as variable virtual hypothesis collections based on Mario Carneiro's metavariable concept. elpwgded is elpwgdedVD using conventional notation. (Contributed by Alan Sare, 23-Apr-2015) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | elpwgdedVD.1 | ⊢ ( 𝜑 ▶ 𝐴 ∈ V ) | |
| elpwgdedVD.2 | ⊢ ( 𝜓 ▶ 𝐴 ⊆ 𝐵 ) | ||
| Assertion | elpwgdedVD | ⊢ ( ( 𝜑 , 𝜓 ) ▶ 𝐴 ∈ 𝒫 𝐵 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elpwgdedVD.1 | ⊢ ( 𝜑 ▶ 𝐴 ∈ V ) | |
| 2 | elpwgdedVD.2 | ⊢ ( 𝜓 ▶ 𝐴 ⊆ 𝐵 ) | |
| 3 | elpwg | ⊢ ( 𝐴 ∈ V → ( 𝐴 ∈ 𝒫 𝐵 ↔ 𝐴 ⊆ 𝐵 ) ) | |
| 4 | 3 | biimpar | ⊢ ( ( 𝐴 ∈ V ∧ 𝐴 ⊆ 𝐵 ) → 𝐴 ∈ 𝒫 𝐵 ) |
| 5 | 1 2 4 | el12 | ⊢ ( ( 𝜑 , 𝜓 ) ▶ 𝐴 ∈ 𝒫 𝐵 ) |