English
There is a canonical continuity of evaluation in the first argument: for each x, the map f ↦ f(x) is continuous from C(X,Y) to Y. This holds in a suitable framework (e.g., LocallyCompactPair).
Русский
Сущестует каноническая непрерывность оценивания по первому аргументу: для каждого x отображение f ↦ f(x) непрерывно от C(X,Y) к Y.
LaTeX
$$$\\text{ContinuousEvalConst } C(X,Y)\\,X\\,Y$;\\ for each x, the map $f \\mapsto f(x)$ is continuous$$
Lean4
instance : ContinuousEvalConst C(X, Y) X Y where
continuous_eval_const x := continuous_def.2 fun U hU ↦ by simpa using isOpen_setOf_mapsTo isCompact_singleton hU