English
The value of fderivWithin is defined via the wrapped derivative construction; it equals the chosen derivative if differentiable, otherwise 0.
Русский
Значение fderivWithin задаётся через обёрнутую конструкцию производной; если существует производная — она выбирается, иначе 0.
LaTeX
$$$\text{fderivWithin } 𝕜 f s x := \text{val_proj} \; (wrapped✝) $$$
Lean4
/-- If `f` has a derivative at `x` within `s`, then `fderivWithin 𝕜 f s x` is such a derivative.
Otherwise, it is set to `0`. We also set it to be zero, if zero is one of possible derivatives. -/
def fderivWithin :=
val_proj @wrapped✝.{}