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Description: An unordered pair belongs to the power class of a class iff each member belongs to the class. (Contributed by NM, 10-Dec-2003) (Proof shortened by Andrew Salmon, 26-Jun-2011) (Proof shortened by OpenAI, 25-Mar-2020)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | prsspw.1 | ⊢ 𝐴 ∈ V | |
| prsspw.2 | ⊢ 𝐵 ∈ V | ||
| Assertion | prsspw | ⊢ ( { 𝐴 , 𝐵 } ⊆ 𝒫 𝐶 ↔ ( 𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | prsspw.1 | ⊢ 𝐴 ∈ V | |
| 2 | prsspw.2 | ⊢ 𝐵 ∈ V | |
| 3 | prsspwg | ⊢ ( ( 𝐴 ∈ V ∧ 𝐵 ∈ V ) → ( { 𝐴 , 𝐵 } ⊆ 𝒫 𝐶 ↔ ( 𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶 ) ) ) | |
| 4 | 1 2 3 | mp2an | ⊢ ( { 𝐴 , 𝐵 } ⊆ 𝒫 𝐶 ↔ ( 𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶 ) ) |