Description: Conditional operator existence. (Contributed by NM, 21-Mar-2011) (Proof shortened by BJ, 1-Sep-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | ifexg | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊 ) → if ( 𝜑 , 𝐴 , 𝐵 ) ∈ V ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elex | ⊢ ( 𝐴 ∈ 𝑉 → 𝐴 ∈ V ) | |
2 | elex | ⊢ ( 𝐵 ∈ 𝑊 → 𝐵 ∈ V ) | |
3 | ifcl | ⊢ ( ( 𝐴 ∈ V ∧ 𝐵 ∈ V ) → if ( 𝜑 , 𝐴 , 𝐵 ) ∈ V ) | |
4 | 1 2 3 | syl2an | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊 ) → if ( 𝜑 , 𝐴 , 𝐵 ) ∈ V ) |