Description: Sethood of certain classes. (Contributed by BJ, 2-Apr-2019)
Ref | Expression | ||
---|---|---|---|
Assertion | bj-clex | ⊢ ( 𝐴 ∈ 𝑉 → { 𝑥 ∣ { 𝑥 } ∈ ( 𝐴 “ 𝐵 ) } ∈ V ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | imaexg | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝐴 “ 𝐵 ) ∈ V ) | |
2 | bj-snsetex | ⊢ ( ( 𝐴 “ 𝐵 ) ∈ V → { 𝑥 ∣ { 𝑥 } ∈ ( 𝐴 “ 𝐵 ) } ∈ V ) | |
3 | 1 2 | syl | ⊢ ( 𝐴 ∈ 𝑉 → { 𝑥 ∣ { 𝑥 } ∈ ( 𝐴 “ 𝐵 ) } ∈ V ) |