One-dimensional iterated derivatives #
This file contains a number of further results on iteratedDerivWithin
that need more imports
than are available in Mathlib/Analysis/Calculus/IteratedDeriv/Defs.lean
.
theorem
iteratedDerivWithin_congr
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{n : โ}
{s : Set ๐}
(h : UniqueDiffOn ๐ s)
{f g : ๐ โ F}
(hfg : Set.EqOn f g s)
:
Set.EqOn (iteratedDerivWithin n f s) (iteratedDerivWithin n g s) s
theorem
iteratedDerivWithin_add
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{n : โ}
{x : ๐}
{s : Set ๐}
(hx : x โ s)
(h : UniqueDiffOn ๐ s)
{f g : ๐ โ F}
(hf : ContDiffOn ๐ (โn) f s)
(hg : ContDiffOn ๐ (โn) g s)
:
iteratedDerivWithin n (f + g) s x = iteratedDerivWithin n f s x + iteratedDerivWithin n g s x
theorem
iteratedDerivWithin_const_add
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{n : โ}
{x : ๐}
{s : Set ๐}
(hx : x โ s)
(h : UniqueDiffOn ๐ s)
{f : ๐ โ F}
(hn : 0 < n)
(c : F)
:
iteratedDerivWithin n (fun (z : ๐) => c + f z) s x = iteratedDerivWithin n f s x
theorem
iteratedDerivWithin_const_neg
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{n : โ}
{x : ๐}
{s : Set ๐}
(hx : x โ s)
(h : UniqueDiffOn ๐ s)
{f : ๐ โ F}
(hn : 0 < n)
(c : F)
:
iteratedDerivWithin n (fun (z : ๐) => c - f z) s x = iteratedDerivWithin n (fun (z : ๐) => -f z) s x
theorem
iteratedDerivWithin_const_smul
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{R : Type u_3}
[Semiring R]
[Module R F]
[SMulCommClass ๐ R F]
[ContinuousConstSMul R F]
{n : โ}
{x : ๐}
{s : Set ๐}
(hx : x โ s)
(h : UniqueDiffOn ๐ s)
{f : ๐ โ F}
(c : R)
(hf : ContDiffOn ๐ (โn) f s)
:
iteratedDerivWithin n (c โข f) s x = c โข iteratedDerivWithin n f s x
theorem
iteratedDerivWithin_const_mul
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{n : โ}
{x : ๐}
{s : Set ๐}
(hx : x โ s)
(h : UniqueDiffOn ๐ s)
(c : ๐)
{f : ๐ โ ๐}
(hf : ContDiffOn ๐ (โn) f s)
:
iteratedDerivWithin n (fun (z : ๐) => c * f z) s x = c * iteratedDerivWithin n f s x
theorem
iteratedDerivWithin_neg
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{n : โ}
{x : ๐}
{s : Set ๐}
(hx : x โ s)
(h : UniqueDiffOn ๐ s)
(f : ๐ โ F)
:
iteratedDerivWithin n (-f) s x = -iteratedDerivWithin n f s x
theorem
iteratedDerivWithin_neg'
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{n : โ}
{x : ๐}
{s : Set ๐}
(hx : x โ s)
(h : UniqueDiffOn ๐ s)
(f : ๐ โ F)
:
iteratedDerivWithin n (fun (z : ๐) => -f z) s x = -iteratedDerivWithin n f s x
theorem
iteratedDerivWithin_sub
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{n : โ}
{x : ๐}
{s : Set ๐}
(hx : x โ s)
(h : UniqueDiffOn ๐ s)
{f g : ๐ โ F}
(hf : ContDiffOn ๐ (โn) f s)
(hg : ContDiffOn ๐ (โn) g s)
:
iteratedDerivWithin n (f - g) s x = iteratedDerivWithin n f s x - iteratedDerivWithin n g s x
theorem
iteratedDeriv_const_smul
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{n : โ}
{f : ๐ โ F}
(h : ContDiff ๐ (โn) f)
(c : ๐)
:
(iteratedDeriv n fun (x : ๐) => f (c * x)) = fun (x : ๐) => c ^ n โข iteratedDeriv n f (c * x)
theorem
iteratedDeriv_const_mul
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{n : โ}
{f : ๐ โ ๐}
(h : ContDiff ๐ (โn) f)
(c : ๐)
:
(iteratedDeriv n fun (x : ๐) => f (c * x)) = fun (x : ๐) => c ^ n * iteratedDeriv n f (c * x)
theorem
iteratedDeriv_neg
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
(n : โ)
(f : ๐ โ F)
(a : ๐)
:
iteratedDeriv n (fun (x : ๐) => -f x) a = -iteratedDeriv n f a
theorem
iteratedDeriv_comp_neg
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
(n : โ)
(f : ๐ โ F)
(a : ๐)
:
iteratedDeriv n (fun (x : ๐) => f (-x)) a = (-1) ^ n โข iteratedDeriv n f (-a)
theorem
Filter.EventuallyEq.iteratedDeriv_eq
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
(n : โ)
{f g : ๐ โ F}
{x : ๐}
(hfg : f =แถ [nhds x] g)
:
iteratedDeriv n f x = iteratedDeriv n g x
theorem
Set.EqOn.iteratedDeriv_of_isOpen
{๐ : Type u_1}
[NontriviallyNormedField ๐]
{F : Type u_2}
[NormedAddCommGroup F]
[NormedSpace ๐ F]
{s : Set ๐}
{f g : ๐ โ F}
(hfg : Set.EqOn f g s)
(hs : IsOpen s)
(n : โ)
:
Set.EqOn (iteratedDeriv n f) (iteratedDeriv n g) s
Invariance of iterated derivatives under translation #
theorem
iteratedDeriv_comp_const_add
{๐ : Type u_1}
{F : Type u_2}
[NontriviallyNormedField ๐]
[NormedAddCommGroup F]
[NormedSpace ๐ F]
(n : โ)
(f : ๐ โ F)
(s : ๐)
:
(iteratedDeriv n fun (z : ๐) => f (s + z)) = fun (t : ๐) => iteratedDeriv n f (s + t)
The iterated derivative commutes with shifting the function by a constant on the left.
theorem
iteratedDeriv_comp_add_const
{๐ : Type u_1}
{F : Type u_2}
[NontriviallyNormedField ๐]
[NormedAddCommGroup F]
[NormedSpace ๐ F]
(n : โ)
(f : ๐ โ F)
(s : ๐)
:
(iteratedDeriv n fun (z : ๐) => f (z + s)) = fun (t : ๐) => iteratedDeriv n f (t + s)
The iterated derivative commutes with shifting the function by a constant on the right.