English
If f and g are continuous within a set s at x, then f -ᵥ g is continuous within s at x.
Русский
Если f и g непрерывны внутри множества s в точке x, то f -ᵥ g непрерывна внутри s в x.
LaTeX
$$$\text{ContinuousWithinAt}(f,s,x) \land \text{ContinuousWithinAt}(g,s,x) \Rightarrow \text{ContinuousWithinAt}(f -ᵥ g,s,x).$$$
Lean4
@[fun_prop]
nonrec theorem vsub {f g : α → P} {x : α} {s : Set α} (hf : ContinuousWithinAt f s x) (hg : ContinuousWithinAt g s x) :
ContinuousWithinAt (fun x ↦ f x -ᵥ g x) s x :=
hf.vsub hg