Description: The evaluation at a class is a function on the universal class. (General form of slotfn ). (Contributed by Mario Carneiro, 22-Sep-2015) (Revised by BJ, 27-Dec-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | bj-evalfn | ⊢ Slot 𝐴 Fn V | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | fvex | ⊢ ( 𝑓 ‘ 𝐴 ) ∈ V | |
| 2 | df-slot | ⊢ Slot 𝐴 = ( 𝑓 ∈ V ↦ ( 𝑓 ‘ 𝐴 ) ) | |
| 3 | 1 2 | fnmpti | ⊢ Slot 𝐴 Fn V |