English
In a finite-dimensional real inner product space, every closed ball is compact.
Русский
В конечномерном вещественном гильбертовом пространстве любая замкнутая сфера (шар) компактна.
LaTeX
$$IsCompact (closedBall x r)$$
Lean4
/-- If `x` and `y` are two points in a finite-dimensional space over `ℝ`, then `Euclidean.dist x y`
is the distance between these points in the metric defined by some inner product space structure on
`E`. -/
nonrec def dist (x y : E) : ℝ :=
dist (toEuclidean x) (toEuclidean y)