Description: If A is a set then the class of cosets by the converse of A is a set. (Contributed by Peter Mazsa, 18-Oct-2019)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | cosscnvex | ⊢ ( 𝐴 ∈ 𝑉 → ≀ ◡ 𝐴 ∈ V ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cnvexg | ⊢ ( 𝐴 ∈ 𝑉 → ◡ 𝐴 ∈ V ) | |
| 2 | cossex | ⊢ ( ◡ 𝐴 ∈ V → ≀ ◡ 𝐴 ∈ V ) | |
| 3 | 1 2 | syl | ⊢ ( 𝐴 ∈ 𝑉 → ≀ ◡ 𝐴 ∈ V ) |