English
Translation in the domain by a fixed a does not change the derivative within a shifted set.
Русский
Сдвиг аргумента на константу a не изменяет производную внутри области после соответствующего сдвига множества.
LaTeX
$$$\\mathrm{derivWithin}(f\\lvert\\!\\!\\; (a+\\cdot), s, x) = \\mathrm{derivWithin}(f, a+\\!\\!\\! s, a+x)$$$
Lean4
/-- Translation in the domain does not change the derivative. -/
theorem derivWithin_comp_const_add : derivWithin (f <| a + ·) s x = derivWithin f (a +ᵥ s) (a + x) := by
simp only [derivWithin, fderivWithin_comp_add_left]