Description: The composition of two sets is a set. (Contributed by SN, 7-Feb-2025)
Ref | Expression | ||
---|---|---|---|
Hypotheses | coexd.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
coexd.2 | ⊢ ( 𝜑 → 𝐵 ∈ 𝑊 ) | ||
Assertion | coexd | ⊢ ( 𝜑 → ( 𝐴 ∘ 𝐵 ) ∈ V ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | coexd.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
2 | coexd.2 | ⊢ ( 𝜑 → 𝐵 ∈ 𝑊 ) | |
3 | coexg | ⊢ ( ( 𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊 ) → ( 𝐴 ∘ 𝐵 ) ∈ V ) | |
4 | 1 2 3 | syl2anc | ⊢ ( 𝜑 → ( 𝐴 ∘ 𝐵 ) ∈ V ) |