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exists_has_deriv_within_at_eq_of_le_of_ge (hab : a ≤ b) (hf : ∀ x ∈ (Icc a b), has_deriv_within_at f (f' x) (Icc a b) x) {m : ℝ} (hma : f' a ≤ m) (hmb : m ≤ f' b) : m ∈ f' '' Icc a b
(ord_connected_Icc.image_has_deriv_within_at hf).out (mem_image_of_mem _ (left_mem_Icc.2 hab)) (mem_image_of_mem _ (right_mem_Icc.2 hab)) ⟨hma, hmb⟩
theorem
exists_has_deriv_within_at_eq_of_le_of_ge
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "has_deriv_within_at" ]
**Darboux's theorem**: if `a ≤ b` and `f' b ≤ m ≤ f' a`, then `f' c = m` for some `c ∈ [a, b]`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_deriv_within_at_forall_lt_or_forall_gt_of_forall_ne {s : set ℝ} (hs : convex ℝ s) (hf : ∀ x ∈ s, has_deriv_within_at f (f' x) s x) {m : ℝ} (hf' : ∀ x ∈ s, f' x ≠ m) : (∀ x ∈ s, f' x < m) ∨ (∀ x ∈ s, m < f' x)
begin contrapose! hf', rcases hf' with ⟨⟨b, hb, hmb⟩, ⟨a, ha, hma⟩⟩, exact (hs.ord_connected.image_has_deriv_within_at hf).out (mem_image_of_mem f' ha) (mem_image_of_mem f' hb) ⟨hma, hmb⟩ end
theorem
has_deriv_within_at_forall_lt_or_forall_gt_of_forall_ne
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "convex", "has_deriv_within_at" ]
If the derivative of a function is never equal to `m`, then either it is always greater than `m`, or it is always less than `m`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diff_cont_on_cl (f : E → F) (s : set E) : Prop
(differentiable_on : differentiable_on 𝕜 f s) (continuous_on : continuous_on f (closure s))
structure
diff_cont_on_cl
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "closure", "continuous_on", "differentiable_on" ]
A predicate saying that a function is differentiable on a set and is continuous on its closure. This is a common assumption in complex analysis.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_on.diff_cont_on_cl (h : differentiable_on 𝕜 f (closure s)) : diff_cont_on_cl 𝕜 f s
⟨h.mono subset_closure, h.continuous_on⟩
lemma
differentiable_on.diff_cont_on_cl
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "closure", "diff_cont_on_cl", "differentiable_on", "subset_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable.diff_cont_on_cl (h : differentiable 𝕜 f) : diff_cont_on_cl 𝕜 f s
⟨h.differentiable_on, h.continuous.continuous_on⟩
lemma
differentiable.diff_cont_on_cl
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "differentiable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed.diff_cont_on_cl_iff (hs : is_closed s) : diff_cont_on_cl 𝕜 f s ↔ differentiable_on 𝕜 f s
⟨λ h, h.differentiable_on, λ h, ⟨h, hs.closure_eq.symm ▸ h.continuous_on⟩⟩
lemma
is_closed.diff_cont_on_cl_iff
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "differentiable_on", "is_closed" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diff_cont_on_cl_univ : diff_cont_on_cl 𝕜 f univ ↔ differentiable 𝕜 f
is_closed_univ.diff_cont_on_cl_iff.trans differentiable_on_univ
lemma
diff_cont_on_cl_univ
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "differentiable", "differentiable_on_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diff_cont_on_cl_const {c : F} : diff_cont_on_cl 𝕜 (λ x : E, c) s
⟨differentiable_on_const c, continuous_on_const⟩
lemma
diff_cont_on_cl_const
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp {g : G → E} {t : set G} (hf : diff_cont_on_cl 𝕜 f s) (hg : diff_cont_on_cl 𝕜 g t) (h : maps_to g t s) : diff_cont_on_cl 𝕜 (f ∘ g) t
⟨hf.1.comp hg.1 h, hf.2.comp hg.2 $ h.closure_of_continuous_on hg.2⟩
lemma
diff_cont_on_cl.comp
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_on_ball [normed_space ℝ E] {x : E} {r : ℝ} (h : diff_cont_on_cl 𝕜 f (ball x r)) : continuous_on f (closed_ball x r)
begin rcases eq_or_ne r 0 with rfl|hr, { rw closed_ball_zero, exact continuous_on_singleton f x }, { rw ← closure_ball x hr, exact h.continuous_on } end
lemma
diff_cont_on_cl.continuous_on_ball
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "closure_ball", "continuous_on", "continuous_on_singleton", "diff_cont_on_cl", "eq_or_ne", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_ball {x : E} {r : ℝ} (hd : differentiable_on 𝕜 f (ball x r)) (hc : continuous_on f (closed_ball x r)) : diff_cont_on_cl 𝕜 f (ball x r)
⟨hd, hc.mono $ closure_ball_subset_closed_ball⟩
lemma
diff_cont_on_cl.mk_ball
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "continuous_on", "diff_cont_on_cl", "differentiable_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_at (h : diff_cont_on_cl 𝕜 f s) (hs : is_open s) (hx : x ∈ s) : differentiable_at 𝕜 f x
h.differentiable_on.differentiable_at $ hs.mem_nhds hx
lemma
diff_cont_on_cl.differentiable_at
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "differentiable_at", "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_at' (h : diff_cont_on_cl 𝕜 f s) (hx : s ∈ 𝓝 x) : differentiable_at 𝕜 f x
h.differentiable_on.differentiable_at hx
lemma
diff_cont_on_cl.differentiable_at'
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "differentiable_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mono (h : diff_cont_on_cl 𝕜 f s) (ht : t ⊆ s) : diff_cont_on_cl 𝕜 f t
⟨h.differentiable_on.mono ht, h.continuous_on.mono (closure_mono ht)⟩
lemma
diff_cont_on_cl.mono
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "closure_mono", "diff_cont_on_cl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add (hf : diff_cont_on_cl 𝕜 f s) (hg : diff_cont_on_cl 𝕜 g s) : diff_cont_on_cl 𝕜 (f + g) s
⟨hf.1.add hg.1, hf.2.add hg.2⟩
lemma
diff_cont_on_cl.add
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_const (hf : diff_cont_on_cl 𝕜 f s) (c : F) : diff_cont_on_cl 𝕜 (λ x, f x + c) s
hf.add diff_cont_on_cl_const
lemma
diff_cont_on_cl.add_const
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "diff_cont_on_cl_const" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
const_add (hf : diff_cont_on_cl 𝕜 f s) (c : F) : diff_cont_on_cl 𝕜 (λ x, c + f x) s
diff_cont_on_cl_const.add hf
lemma
diff_cont_on_cl.const_add
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg (hf : diff_cont_on_cl 𝕜 f s) : diff_cont_on_cl 𝕜 (-f) s
⟨hf.1.neg, hf.2.neg⟩
lemma
diff_cont_on_cl.neg
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub (hf : diff_cont_on_cl 𝕜 f s) (hg : diff_cont_on_cl 𝕜 g s) : diff_cont_on_cl 𝕜 (f - g) s
⟨hf.1.sub hg.1, hf.2.sub hg.2⟩
lemma
diff_cont_on_cl.sub
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_const (hf : diff_cont_on_cl 𝕜 f s) (c : F) : diff_cont_on_cl 𝕜 (λ x, f x - c) s
hf.sub diff_cont_on_cl_const
lemma
diff_cont_on_cl.sub_const
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "diff_cont_on_cl_const" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
const_sub (hf : diff_cont_on_cl 𝕜 f s) (c : F) : diff_cont_on_cl 𝕜 (λ x, c - f x) s
diff_cont_on_cl_const.sub hf
lemma
diff_cont_on_cl.const_sub
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
const_smul {R : Type*} [semiring R] [module R F] [smul_comm_class 𝕜 R F] [has_continuous_const_smul R F] (hf : diff_cont_on_cl 𝕜 f s) (c : R) : diff_cont_on_cl 𝕜 (c • f) s
⟨hf.1.const_smul c, hf.2.const_smul c⟩
lemma
diff_cont_on_cl.const_smul
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "has_continuous_const_smul", "module", "semiring", "smul_comm_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul {𝕜' : Type*} [nontrivially_normed_field 𝕜'] [normed_algebra 𝕜 𝕜'] [normed_space 𝕜' F] [is_scalar_tower 𝕜 𝕜' F] {c : E → 𝕜'} {f : E → F} {s : set E} (hc : diff_cont_on_cl 𝕜 c s) (hf : diff_cont_on_cl 𝕜 f s) : diff_cont_on_cl 𝕜 (λ x, c x • f x) s
⟨hc.1.smul hf.1, hc.2.smul hf.2⟩
lemma
diff_cont_on_cl.smul
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "is_scalar_tower", "nontrivially_normed_field", "normed_algebra", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_const {𝕜' : Type*} [nontrivially_normed_field 𝕜'] [normed_algebra 𝕜 𝕜'] [normed_space 𝕜' F] [is_scalar_tower 𝕜 𝕜' F] {c : E → 𝕜'} {s : set E} (hc : diff_cont_on_cl 𝕜 c s) (y : F) : diff_cont_on_cl 𝕜 (λ x, c x • y) s
hc.smul diff_cont_on_cl_const
lemma
diff_cont_on_cl.smul_const
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "diff_cont_on_cl_const", "is_scalar_tower", "nontrivially_normed_field", "normed_algebra", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv {f : E → 𝕜} (hf : diff_cont_on_cl 𝕜 f s) (h₀ : ∀ x ∈ closure s, f x ≠ 0) : diff_cont_on_cl 𝕜 f⁻¹ s
⟨differentiable_on_inv.comp hf.1 $ λ x hx, h₀ _ (subset_closure hx), hf.2.inv₀ h₀⟩
lemma
diff_cont_on_cl.inv
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "closure", "diff_cont_on_cl", "subset_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable.comp_diff_cont_on_cl {g : G → E} {t : set G} (hf : differentiable 𝕜 f) (hg : diff_cont_on_cl 𝕜 g t) : diff_cont_on_cl 𝕜 (f ∘ g) t
hf.diff_cont_on_cl.comp hg (maps_to_image _ _)
lemma
differentiable.comp_diff_cont_on_cl
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "differentiable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_on.diff_cont_on_cl_ball {U : set E} {c : E} {R : ℝ} (hf : differentiable_on 𝕜 f U) (hc : closed_ball c R ⊆ U) : diff_cont_on_cl 𝕜 f (ball c R)
diff_cont_on_cl.mk_ball (hf.mono (ball_subset_closed_ball.trans hc)) (hf.continuous_on.mono hc)
lemma
differentiable_on.diff_cont_on_cl_ball
analysis.calculus
src/analysis/calculus/diff_cont_on_cl.lean
[ "analysis.calculus.deriv.inv" ]
[ "diff_cont_on_cl", "diff_cont_on_cl.mk_ball", "differentiable_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dslope (f : 𝕜 → E) (a : 𝕜) : 𝕜 → E
update (slope f a) a (deriv f a)
def
dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "deriv", "slope", "update" ]
`dslope f a b` is defined as `slope f a b = (b - a)⁻¹ • (f b - f a)` for `a ≠ b` and `deriv f a` for `a = b`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dslope_same (f : 𝕜 → E) (a : 𝕜) : dslope f a a = deriv f a
update_same _ _ _
lemma
dslope_same
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "deriv", "dslope", "update_same" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dslope_of_ne (f : 𝕜 → E) (h : b ≠ a) : dslope f a b = slope f a b
update_noteq h _ _
lemma
dslope_of_ne
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "dslope", "slope", "update_noteq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_linear_map.dslope_comp {F : Type*} [normed_add_comm_group F] [normed_space 𝕜 F] (f : E →L[𝕜] F) (g : 𝕜 → E) (a b : 𝕜) (H : a = b → differentiable_at 𝕜 g a) : dslope (f ∘ g) a b = f (dslope g a b)
begin rcases eq_or_ne b a with rfl|hne, { simp only [dslope_same], exact (f.has_fderiv_at.comp_has_deriv_at b (H rfl).has_deriv_at).deriv }, { simpa only [dslope_of_ne _ hne] using f.to_linear_map.slope_comp g a b } end
lemma
continuous_linear_map.dslope_comp
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "deriv", "differentiable_at", "dslope", "dslope_of_ne", "dslope_same", "eq_or_ne", "has_deriv_at", "normed_add_comm_group", "normed_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_on_dslope_slope (f : 𝕜 → E) (a : 𝕜) : eq_on (dslope f a) (slope f a) {a}ᶜ
λ b, dslope_of_ne f
lemma
eq_on_dslope_slope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "dslope", "dslope_of_ne", "slope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dslope_eventually_eq_slope_of_ne (f : 𝕜 → E) (h : b ≠ a) : dslope f a =ᶠ[𝓝 b] slope f a
(eq_on_dslope_slope f a).eventually_eq_of_mem (is_open_ne.mem_nhds h)
lemma
dslope_eventually_eq_slope_of_ne
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "dslope", "eq_on_dslope_slope", "slope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dslope_eventually_eq_slope_punctured_nhds (f : 𝕜 → E) : dslope f a =ᶠ[𝓝[≠] a] slope f a
(eq_on_dslope_slope f a).eventually_eq_of_mem self_mem_nhds_within
lemma
dslope_eventually_eq_slope_punctured_nhds
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "dslope", "eq_on_dslope_slope", "self_mem_nhds_within", "slope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_smul_dslope (f : 𝕜 → E) (a b : 𝕜) : (b - a) • dslope f a b = f b - f a
by rcases eq_or_ne b a with rfl | hne; simp [dslope_of_ne, *]
lemma
sub_smul_dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "dslope", "dslope_of_ne", "eq_or_ne" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dslope_sub_smul_of_ne (f : 𝕜 → E) (h : b ≠ a) : dslope (λ x, (x - a) • f x) a b = f b
by rw [dslope_of_ne _ h, slope_sub_smul _ h.symm]
lemma
dslope_sub_smul_of_ne
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "dslope", "dslope_of_ne", "slope_sub_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_on_dslope_sub_smul (f : 𝕜 → E) (a : 𝕜) : eq_on (dslope (λ x, (x - a) • f x) a) f {a}ᶜ
λ b, dslope_sub_smul_of_ne f
lemma
eq_on_dslope_sub_smul
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "dslope", "dslope_sub_smul_of_ne" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dslope_sub_smul [decidable_eq 𝕜] (f : 𝕜 → E) (a : 𝕜) : dslope (λ x, (x - a) • f x) a = update f a (deriv (λ x, (x - a) • f x) a)
eq_update_iff.2 ⟨dslope_same _ _, eq_on_dslope_sub_smul f a⟩
lemma
dslope_sub_smul
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "deriv", "dslope", "eq_on_dslope_sub_smul", "update" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at_dslope_same : continuous_at (dslope f a) a ↔ differentiable_at 𝕜 f a
by simp only [dslope, continuous_at_update_same, ← has_deriv_at_deriv_iff, has_deriv_at_iff_tendsto_slope]
lemma
continuous_at_dslope_same
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "continuous_at", "continuous_at_update_same", "differentiable_at", "dslope", "has_deriv_at_deriv_iff", "has_deriv_at_iff_tendsto_slope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_within_at.of_dslope (h : continuous_within_at (dslope f a) s b) : continuous_within_at f s b
have continuous_within_at (λ x, (x - a) • dslope f a x + f a) s b, from ((continuous_within_at_id.sub continuous_within_at_const).smul h).add continuous_within_at_const, by simpa only [sub_smul_dslope, sub_add_cancel] using this
lemma
continuous_within_at.of_dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "continuous_within_at", "continuous_within_at_const", "dslope", "sub_smul_dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at.of_dslope (h : continuous_at (dslope f a) b) : continuous_at f b
(continuous_within_at_univ _ _).1 h.continuous_within_at.of_dslope
lemma
continuous_at.of_dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "continuous_at", "continuous_within_at_univ", "dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_on.of_dslope (h : continuous_on (dslope f a) s) : continuous_on f s
λ x hx, (h x hx).of_dslope
lemma
continuous_on.of_dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "continuous_on", "dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_within_at_dslope_of_ne (h : b ≠ a) : continuous_within_at (dslope f a) s b ↔ continuous_within_at f s b
begin refine ⟨continuous_within_at.of_dslope, λ hc, _⟩, simp only [dslope, continuous_within_at_update_of_ne h], exact ((continuous_within_at_id.sub continuous_within_at_const).inv₀ (sub_ne_zero.2 h)).smul (hc.sub continuous_within_at_const) end
lemma
continuous_within_at_dslope_of_ne
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "continuous_within_at", "continuous_within_at_const", "continuous_within_at_update_of_ne", "dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at_dslope_of_ne (h : b ≠ a) : continuous_at (dslope f a) b ↔ continuous_at f b
by simp only [← continuous_within_at_univ, continuous_within_at_dslope_of_ne h]
lemma
continuous_at_dslope_of_ne
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "continuous_at", "continuous_within_at_dslope_of_ne", "continuous_within_at_univ", "dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_on_dslope (h : s ∈ 𝓝 a) : continuous_on (dslope f a) s ↔ continuous_on f s ∧ differentiable_at 𝕜 f a
begin refine ⟨λ hc, ⟨hc.of_dslope, continuous_at_dslope_same.1 $ hc.continuous_at h⟩, _⟩, rintro ⟨hc, hd⟩ x hx, rcases eq_or_ne x a with rfl | hne, exacts [(continuous_at_dslope_same.2 hd).continuous_within_at, (continuous_within_at_dslope_of_ne hne).2 (hc x hx)] end
lemma
continuous_on_dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "continuous_on", "continuous_within_at", "continuous_within_at_dslope_of_ne", "differentiable_at", "dslope", "eq_or_ne" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_within_at.of_dslope (h : differentiable_within_at 𝕜 (dslope f a) s b) : differentiable_within_at 𝕜 f s b
by simpa only [id, sub_smul_dslope f a, sub_add_cancel] using ((differentiable_within_at_id.sub_const a).smul h).add_const (f a)
lemma
differentiable_within_at.of_dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "differentiable_within_at", "dslope", "sub_smul_dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_at.of_dslope (h : differentiable_at 𝕜 (dslope f a) b) : differentiable_at 𝕜 f b
differentiable_within_at_univ.1 h.differentiable_within_at.of_dslope
lemma
differentiable_at.of_dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "differentiable_at", "dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_on.of_dslope (h : differentiable_on 𝕜 (dslope f a) s) : differentiable_on 𝕜 f s
λ x hx, (h x hx).of_dslope
lemma
differentiable_on.of_dslope
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "differentiable_on", "dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_within_at_dslope_of_ne (h : b ≠ a) : differentiable_within_at 𝕜 (dslope f a) s b ↔ differentiable_within_at 𝕜 f s b
begin refine ⟨differentiable_within_at.of_dslope, λ hd, _⟩, refine (((differentiable_within_at_id.sub_const a).inv (sub_ne_zero.2 h)).smul (hd.sub_const (f a))).congr_of_eventually_eq _ (dslope_of_ne _ h), refine (eq_on_dslope_slope _ _).eventually_eq_of_mem _, exact mem_nhds_within_of_mem_nhds (is_open_ne....
lemma
differentiable_within_at_dslope_of_ne
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "differentiable_within_at", "dslope", "dslope_of_ne", "eq_on_dslope_slope", "mem_nhds_within_of_mem_nhds" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_on_dslope_of_nmem (h : a ∉ s) : differentiable_on 𝕜 (dslope f a) s ↔ differentiable_on 𝕜 f s
forall_congr $ λ x, forall_congr $ λ hx, differentiable_within_at_dslope_of_ne $ ne_of_mem_of_not_mem hx h
lemma
differentiable_on_dslope_of_nmem
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "differentiable_on", "differentiable_within_at_dslope_of_ne", "dslope", "ne_of_mem_of_not_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_at_dslope_of_ne (h : b ≠ a) : differentiable_at 𝕜 (dslope f a) b ↔ differentiable_at 𝕜 f b
by simp only [← differentiable_within_at_univ, differentiable_within_at_dslope_of_ne h]
lemma
differentiable_at_dslope_of_ne
analysis.calculus
src/analysis/calculus/dslope.lean
[ "analysis.calculus.deriv.slope", "analysis.calculus.deriv.inv" ]
[ "differentiable_at", "differentiable_within_at_dslope_of_ne", "differentiable_within_at_univ", "dslope" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fderiv_at_boundary_of_tendsto_fderiv {f : E → F} {s : set E} {x : E} {f' : E →L[ℝ] F} (f_diff : differentiable_on ℝ f s) (s_conv : convex ℝ s) (s_open : is_open s) (f_cont : ∀y ∈ closure s, continuous_within_at f s y) (h : tendsto (λy, fderiv ℝ f y) (𝓝[s] x) (𝓝 f')) : has_fderiv_within_at f f' (closure s)...
begin classical, -- one can assume without loss of generality that `x` belongs to the closure of `s`, as the -- statement is empty otherwise by_cases hx : x ∉ closure s, { rw ← closure_closure at hx, exact has_fderiv_within_at_of_not_mem_closure hx }, push_neg at hx, rw [has_fderiv_within_at, has_fderiv_a...
theorem
has_fderiv_at_boundary_of_tendsto_fderiv
analysis.calculus
src/analysis/calculus/extend_deriv.lean
[ "analysis.calculus.mean_value" ]
[ "asymptotics.is_o_iff", "bound", "closure", "closure_closure", "closure_mono", "closure_prod_eq", "continuous_within_at", "continuous_within_at.closure_le", "continuous_within_at.mono", "convex", "convex_ball", "differentiable_at", "differentiable_at.fderiv_within", "differentiable_on", ...
If a function `f` is differentiable in a convex open set and continuous on its closure, and its derivative converges to a limit `f'` at a point on the boundary, then `f` is differentiable there with derivative `f'`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_deriv_at_interval_left_endpoint_of_tendsto_deriv {s : set ℝ} {e : E} {a : ℝ} {f : ℝ → E} (f_diff : differentiable_on ℝ f s) (f_lim : continuous_within_at f s a) (hs : s ∈ 𝓝[>] a) (f_lim' : tendsto (λx, deriv f x) (𝓝[>] a) (𝓝 e)) : has_deriv_within_at f e (Ici a) a
begin /- This is a specialization of `has_fderiv_at_boundary_of_tendsto_fderiv`. To be in the setting of this theorem, we need to work on an open interval with closure contained in `s ∪ {a}`, that we call `t = (a, b)`. Then, we check all the assumptions of this theorem and we apply it. -/ obtain ⟨b, ab : a < b,...
lemma
has_deriv_at_interval_left_endpoint_of_tendsto_deriv
analysis.calculus
src/analysis/calculus/extend_deriv.lean
[ "analysis.calculus.mean_value" ]
[ "Icc_mem_nhds_within_Ici", "closure", "closure_Ioo", "continuous_within_at", "convex", "convex_Ioo", "deriv", "differentiable_on", "fderiv", "has_deriv_within_at", "has_deriv_within_at_iff_has_fderiv_within_at", "has_fderiv_at_boundary_of_tendsto_fderiv", "is_bounded_bilinear_map", "is_bou...
If a function is differentiable on the right of a point `a : ℝ`, continuous at `a`, and its derivative also converges at `a`, then `f` is differentiable on the right at `a`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_deriv_at_interval_right_endpoint_of_tendsto_deriv {s : set ℝ} {e : E} {a : ℝ} {f : ℝ → E} (f_diff : differentiable_on ℝ f s) (f_lim : continuous_within_at f s a) (hs : s ∈ 𝓝[<] a) (f_lim' : tendsto (λx, deriv f x) (𝓝[<] a) (𝓝 e)) : has_deriv_within_at f e (Iic a) a
begin /- This is a specialization of `has_fderiv_at_boundary_of_differentiable`. To be in the setting of this theorem, we need to work on an open interval with closure contained in `s ∪ {a}`, that we call `t = (b, a)`. Then, we check all the assumptions of this theorem and we apply it. -/ obtain ⟨b, ba, sab⟩ : ...
lemma
has_deriv_at_interval_right_endpoint_of_tendsto_deriv
analysis.calculus
src/analysis/calculus/extend_deriv.lean
[ "analysis.calculus.mean_value" ]
[ "Icc_mem_nhds_within_Iic", "closure", "closure_Ioo", "continuous_within_at", "convex", "convex_Ioo", "deriv", "differentiable_on", "fderiv", "has_deriv_within_at", "has_deriv_within_at_iff_has_fderiv_within_at", "has_fderiv_at_boundary_of_tendsto_fderiv", "is_bounded_bilinear_map", "is_bou...
If a function is differentiable on the left of a point `a : ℝ`, continuous at `a`, and its derivative also converges at `a`, then `f` is differentiable on the left at `a`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_deriv_at_of_has_deriv_at_of_ne {f g : ℝ → E} {x : ℝ} (f_diff : ∀ y ≠ x, has_deriv_at f (g y) y) (hf : continuous_at f x) (hg : continuous_at g x) : has_deriv_at f (g x) x
begin have A : has_deriv_within_at f (g x) (Ici x) x, { have diff : differentiable_on ℝ f (Ioi x) := λy hy, (f_diff y (ne_of_gt hy)).differentiable_at.differentiable_within_at, -- next line is the nontrivial bit of this proof, appealing to differentiability -- extension results. apply has_deriv_at...
lemma
has_deriv_at_of_has_deriv_at_of_ne
analysis.calculus
src/analysis/calculus/extend_deriv.lean
[ "analysis.calculus.mean_value" ]
[ "continuous_at", "differentiable_at.differentiable_within_at", "differentiable_on", "has_deriv_at", "has_deriv_at_interval_left_endpoint_of_tendsto_deriv", "has_deriv_at_interval_right_endpoint_of_tendsto_deriv", "has_deriv_within_at", "self_mem_nhds_within" ]
If a real function `f` has a derivative `g` everywhere but at a point, and `f` and `g` are continuous at this point, then `g` is also the derivative of `f` at this point.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_deriv_at_of_has_deriv_at_of_ne' {f g : ℝ → E} {x : ℝ} (f_diff : ∀ y ≠ x, has_deriv_at f (g y) y) (hf : continuous_at f x) (hg : continuous_at g x) (y : ℝ) : has_deriv_at f (g y) y
begin rcases eq_or_ne y x with rfl|hne, { exact has_deriv_at_of_has_deriv_at_of_ne f_diff hf hg }, { exact f_diff y hne } end
lemma
has_deriv_at_of_has_deriv_at_of_ne'
analysis.calculus
src/analysis/calculus/extend_deriv.lean
[ "analysis.calculus.mean_value" ]
[ "continuous_at", "eq_or_ne", "has_deriv_at", "has_deriv_at_of_has_deriv_at_of_ne" ]
If a real function `f` has a derivative `g` everywhere but at a point, and `f` and `g` are continuous at this point, then `g` is the derivative of `f` everywhere.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_at.has_strict_fderiv_at (h : has_fpower_series_at f p x) : has_strict_fderiv_at f (continuous_multilinear_curry_fin1 𝕜 E F (p 1)) x
begin refine h.is_O_image_sub_norm_mul_norm_sub.trans_is_o (is_o.of_norm_right _), refine is_o_iff_exists_eq_mul.2 ⟨λ y, ‖y - (x, x)‖, _, eventually_eq.rfl⟩, refine (continuous_id.sub continuous_const).norm.tendsto' _ _ _, rw [_root_.id, sub_self, norm_zero] end
lemma
has_fpower_series_at.has_strict_fderiv_at
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "continuous_const", "continuous_multilinear_curry_fin1", "has_fpower_series_at", "has_strict_fderiv_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_at.has_fderiv_at (h : has_fpower_series_at f p x) : has_fderiv_at f (continuous_multilinear_curry_fin1 𝕜 E F (p 1)) x
h.has_strict_fderiv_at.has_fderiv_at
lemma
has_fpower_series_at.has_fderiv_at
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "continuous_multilinear_curry_fin1", "has_fderiv_at", "has_fpower_series_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_at.differentiable_at (h : has_fpower_series_at f p x) : differentiable_at 𝕜 f x
h.has_fderiv_at.differentiable_at
lemma
has_fpower_series_at.differentiable_at
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "differentiable_at", "has_fpower_series_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
analytic_at.differentiable_at : analytic_at 𝕜 f x → differentiable_at 𝕜 f x
| ⟨p, hp⟩ := hp.differentiable_at
lemma
analytic_at.differentiable_at
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "analytic_at", "differentiable_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
analytic_at.differentiable_within_at (h : analytic_at 𝕜 f x) : differentiable_within_at 𝕜 f s x
h.differentiable_at.differentiable_within_at
lemma
analytic_at.differentiable_within_at
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "analytic_at", "differentiable_within_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_at.fderiv_eq (h : has_fpower_series_at f p x) : fderiv 𝕜 f x = continuous_multilinear_curry_fin1 𝕜 E F (p 1)
h.has_fderiv_at.fderiv
lemma
has_fpower_series_at.fderiv_eq
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "continuous_multilinear_curry_fin1", "fderiv", "has_fpower_series_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_on_ball.differentiable_on [complete_space F] (h : has_fpower_series_on_ball f p x r) : differentiable_on 𝕜 f (emetric.ball x r)
λ y hy, (h.analytic_at_of_mem hy).differentiable_within_at
lemma
has_fpower_series_on_ball.differentiable_on
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "complete_space", "differentiable_on", "differentiable_within_at", "emetric.ball", "has_fpower_series_on_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
analytic_on.differentiable_on (h : analytic_on 𝕜 f s) : differentiable_on 𝕜 f s
λ y hy, (h y hy).differentiable_within_at
lemma
analytic_on.differentiable_on
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "analytic_on", "differentiable_on", "differentiable_within_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_on_ball.has_fderiv_at [complete_space F] (h : has_fpower_series_on_ball f p x r) {y : E} (hy : (‖y‖₊ : ℝ≥0∞) < r) : has_fderiv_at f (continuous_multilinear_curry_fin1 𝕜 E F (p.change_origin y 1)) (x + y)
(h.change_origin hy).has_fpower_series_at.has_fderiv_at
lemma
has_fpower_series_on_ball.has_fderiv_at
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "complete_space", "continuous_multilinear_curry_fin1", "has_fderiv_at", "has_fpower_series_at.has_fderiv_at", "has_fpower_series_on_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_on_ball.fderiv_eq [complete_space F] (h : has_fpower_series_on_ball f p x r) {y : E} (hy : (‖y‖₊ : ℝ≥0∞) < r) : fderiv 𝕜 f (x + y) = continuous_multilinear_curry_fin1 𝕜 E F (p.change_origin y 1)
(h.has_fderiv_at hy).fderiv
lemma
has_fpower_series_on_ball.fderiv_eq
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "complete_space", "continuous_multilinear_curry_fin1", "fderiv", "has_fpower_series_on_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_on_ball.fderiv [complete_space F] (h : has_fpower_series_on_ball f p x r) : has_fpower_series_on_ball (fderiv 𝕜 f) ((continuous_multilinear_curry_fin1 𝕜 E F : (E [×1]→L[𝕜] F) →L[𝕜] (E →L[𝕜] F)) .comp_formal_multilinear_series (p.change_origin_series 1)) x r
begin suffices A : has_fpower_series_on_ball (λ z, continuous_multilinear_curry_fin1 𝕜 E F (p.change_origin (z - x) 1)) ((continuous_multilinear_curry_fin1 𝕜 E F : (E [×1]→L[𝕜] F) →L[𝕜] (E →L[𝕜] F)) .comp_formal_multilinear_series (p.change_origin_series 1)) x r, { apply A.congr, assume z...
lemma
has_fpower_series_on_ball.fderiv
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "complete_space", "continuous_multilinear_curry_fin1", "emetric.mem_ball", "fderiv", "has_fpower_series_on_ball" ]
If a function has a power series on a ball, then so does its derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
analytic_on.fderiv [complete_space F] (h : analytic_on 𝕜 f s) : analytic_on 𝕜 (fderiv 𝕜 f) s
begin assume y hy, rcases h y hy with ⟨p, r, hp⟩, exact hp.fderiv.analytic_at, end
lemma
analytic_on.fderiv
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "analytic_on", "complete_space", "fderiv" ]
If a function is analytic on a set `s`, so is its Fréchet derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
analytic_on.iterated_fderiv [complete_space F] (h : analytic_on 𝕜 f s) (n : ℕ) : analytic_on 𝕜 (iterated_fderiv 𝕜 n f) s
begin induction n with n IH, { rw iterated_fderiv_zero_eq_comp, exact ((continuous_multilinear_curry_fin0 𝕜 E F).symm : F →L[𝕜] (E [×0]→L[𝕜] F)) .comp_analytic_on h }, { rw iterated_fderiv_succ_eq_comp_left, apply (continuous_multilinear_curry_left_equiv 𝕜 (λ (i : fin (n + 1)), E) F) .to_c...
lemma
analytic_on.iterated_fderiv
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "analytic_on", "complete_space", "continuous_multilinear_curry_fin0", "continuous_multilinear_curry_left_equiv", "iterated_fderiv", "iterated_fderiv_succ_eq_comp_left", "iterated_fderiv_zero_eq_comp" ]
If a function is analytic on a set `s`, so are its successive Fréchet derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
analytic_on.cont_diff_on [complete_space F] (h : analytic_on 𝕜 f s) {n : ℕ∞} : cont_diff_on 𝕜 n f s
begin let t := {x | analytic_at 𝕜 f x}, suffices : cont_diff_on 𝕜 n f t, from this.mono h, have H : analytic_on 𝕜 f t := λ x hx, hx, have t_open : is_open t := is_open_analytic_at 𝕜 f, apply cont_diff_on_of_continuous_on_differentiable_on, { assume m hm, apply (H.iterated_fderiv m).continuous_on.con...
lemma
analytic_on.cont_diff_on
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "analytic_at", "analytic_on", "complete_space", "cont_diff_on", "cont_diff_on_of_continuous_on_differentiable_on", "continuous_on.congr", "differentiable_on.congr", "is_open", "is_open_analytic_at", "iterated_fderiv_within_of_is_open" ]
An analytic function is infinitely differentiable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_at.has_strict_deriv_at (h : has_fpower_series_at f p x) : has_strict_deriv_at f (p 1 (λ _, 1)) x
h.has_strict_fderiv_at.has_strict_deriv_at
lemma
has_fpower_series_at.has_strict_deriv_at
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "has_fpower_series_at", "has_strict_deriv_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_at.has_deriv_at (h : has_fpower_series_at f p x) : has_deriv_at f (p 1 (λ _, 1)) x
h.has_strict_deriv_at.has_deriv_at
lemma
has_fpower_series_at.has_deriv_at
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "has_deriv_at", "has_fpower_series_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_at.deriv (h : has_fpower_series_at f p x) : deriv f x = p 1 (λ _, 1)
h.has_deriv_at.deriv
lemma
has_fpower_series_at.deriv
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "deriv", "has_fpower_series_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
analytic_on.deriv [complete_space F] (h : analytic_on 𝕜 f s) : analytic_on 𝕜 (deriv f) s
(continuous_linear_map.apply 𝕜 F (1 : 𝕜)).comp_analytic_on h.fderiv
lemma
analytic_on.deriv
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "analytic_on", "complete_space", "continuous_linear_map.apply", "deriv" ]
If a function is analytic on a set `s`, so is its derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
analytic_on.iterated_deriv [complete_space F] (h : analytic_on 𝕜 f s) (n : ℕ) : analytic_on 𝕜 (deriv^[n] f) s
begin induction n with n IH, { exact h }, { simpa only [function.iterate_succ', function.comp_app] using IH.deriv } end
lemma
analytic_on.iterated_deriv
analysis.calculus
src/analysis/calculus/fderiv_analytic.lean
[ "analysis.analytic.basic", "analysis.calculus.deriv.basic", "analysis.calculus.cont_diff_def" ]
[ "analytic_on", "complete_space", "deriv", "function.iterate_succ'" ]
If a function is analytic on a set `s`, so are its successive derivatives.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measurable_apply₂ [measurable_space E] [opens_measurable_space E] [second_countable_topology E] [second_countable_topology (E →L[𝕜] F)] [measurable_space F] [borel_space F] : measurable (λ p : (E →L[𝕜] F) × E, p.1 p.2)
is_bounded_bilinear_map_apply.continuous.measurable
lemma
continuous_linear_map.measurable_apply₂
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "borel_space", "measurable", "measurable_space", "opens_measurable_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
A (f : E → F) (L : E →L[𝕜] F) (r ε : ℝ) : set E
{x | ∃ r' ∈ Ioc (r/2) r, ∀ y z ∈ ball x r', ‖f z - f y - L (z-y)‖ ≤ ε * r}
def
fderiv_measurable_aux.A
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[]
The set `A f L r ε` is the set of points `x` around which the function `f` is well approximated at scale `r` by the linear map `L`, up to an error `ε`. We tweak the definition to make sure that this is an open set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
B (f : E → F) (K : set (E →L[𝕜] F)) (r s ε : ℝ) : set E
⋃ (L ∈ K), (A f L r ε) ∩ (A f L s ε)
def
fderiv_measurable_aux.B
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[]
The set `B f K r s ε` is the set of points `x` around which there exists a continuous linear map `L` belonging to `K` (a given set of continuous linear maps) that approximates well the function `f` (up to an error `ε`), simultaneously at scales `r` and `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
D (f : E → F) (K : set (E →L[𝕜] F)) : set E
⋂ (e : ℕ), ⋃ (n : ℕ), ⋂ (p ≥ n) (q ≥ n), B f K ((1/2) ^ p) ((1/2) ^ q) ((1/2) ^ e)
def
fderiv_measurable_aux.D
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[]
The set `D f K` is a complicated set constructed using countable intersections and unions. Its main use is that, when `K` is complete, it is exactly the set of points where `f` is differentiable, with a derivative in `K`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_A (L : E →L[𝕜] F) (r ε : ℝ) : is_open (A f L r ε)
begin rw metric.is_open_iff, rintros x ⟨r', r'_mem, hr'⟩, obtain ⟨s, s_gt, s_lt⟩ : ∃ (s : ℝ), r / 2 < s ∧ s < r' := exists_between r'_mem.1, have : s ∈ Ioc (r/2) r := ⟨s_gt, le_of_lt (s_lt.trans_le r'_mem.2)⟩, refine ⟨r' - s, by linarith, λ x' hx', ⟨s, this, _⟩⟩, have B : ball x' s ⊆ ball x r' := ball_subse...
lemma
fderiv_measurable_aux.is_open_A
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "exists_between", "is_open", "metric.is_open_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_B {K : set (E →L[𝕜] F)} {r s ε : ℝ} : is_open (B f K r s ε)
by simp [B, is_open_Union, is_open.inter, is_open_A]
lemma
fderiv_measurable_aux.is_open_B
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "is_open", "is_open.inter", "is_open_Union" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
A_mono (L : E →L[𝕜] F) (r : ℝ) {ε δ : ℝ} (h : ε ≤ δ) : A f L r ε ⊆ A f L r δ
begin rintros x ⟨r', r'r, hr'⟩, refine ⟨r', r'r, λ y hy z hz, (hr' y hy z hz).trans (mul_le_mul_of_nonneg_right h _)⟩, linarith [mem_ball.1 hy, r'r.2, @dist_nonneg _ _ y x], end
lemma
fderiv_measurable_aux.A_mono
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "dist_nonneg", "mul_le_mul_of_nonneg_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_of_mem_A {r ε : ℝ} {L : E →L[𝕜] F} {x : E} (hx : x ∈ A f L r ε) {y z : E} (hy : y ∈ closed_ball x (r/2)) (hz : z ∈ closed_ball x (r/2)) : ‖f z - f y - L (z-y)‖ ≤ ε * r
begin rcases hx with ⟨r', r'mem, hr'⟩, exact hr' _ ((mem_closed_ball.1 hy).trans_lt r'mem.1) _ ((mem_closed_ball.1 hz).trans_lt r'mem.1) end
lemma
fderiv_measurable_aux.le_of_mem_A
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_A_of_differentiable {ε : ℝ} (hε : 0 < ε) {x : E} (hx : differentiable_at 𝕜 f x) : ∃ R > 0, ∀ r ∈ Ioo (0 : ℝ) R, x ∈ A f (fderiv 𝕜 f x) r ε
begin have := hx.has_fderiv_at, simp only [has_fderiv_at, has_fderiv_at_filter, is_o_iff] at this, rcases eventually_nhds_iff_ball.1 (this (half_pos hε)) with ⟨R, R_pos, hR⟩, refine ⟨R, R_pos, λ r hr, _⟩, have : r ∈ Ioc (r/2) r := ⟨half_lt_self hr.1, le_rfl⟩, refine ⟨r, this, λ y hy z hz, _⟩, calc ‖f z -...
lemma
fderiv_measurable_aux.mem_A_of_differentiable
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "continuous_linear_map.map_sub", "differentiable_at", "fderiv", "half_pos", "has_fderiv_at", "has_fderiv_at_filter", "mul_le_mul_of_nonneg_left", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_sub_le_of_mem_A {c : 𝕜} (hc : 1 < ‖c‖) {r ε : ℝ} (hε : 0 < ε) (hr : 0 < r) {x : E} {L₁ L₂ : E →L[𝕜] F} (h₁ : x ∈ A f L₁ r ε) (h₂ : x ∈ A f L₂ r ε) : ‖L₁ - L₂‖ ≤ 4 * ‖c‖ * ε
begin have : 0 ≤ 4 * ‖c‖ * ε := mul_nonneg (mul_nonneg (by norm_num : (0 : ℝ) ≤ 4) (norm_nonneg _)) hε.le, refine op_norm_le_of_shell (half_pos hr) this hc _, assume y ley ylt, rw [div_div, div_le_iff' (mul_pos (by norm_num : (0 : ℝ) < 2) (zero_lt_one.trans hc))] at ley, calc ‖(L₁ - L₂) y‖ =...
lemma
fderiv_measurable_aux.norm_sub_le_of_mem_A
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "dist_self", "div_div", "div_le_iff'", "half_pos", "mul_le_mul_of_nonneg_left", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_set_subset_D : {x | differentiable_at 𝕜 f x ∧ fderiv 𝕜 f x ∈ K} ⊆ D f K
begin assume x hx, rw [D, mem_Inter], assume e, have : (0 : ℝ) < (1/2) ^ e := pow_pos (by norm_num) _, rcases mem_A_of_differentiable this hx.1 with ⟨R, R_pos, hR⟩, obtain ⟨n, hn⟩ : ∃ (n : ℕ), (1/2) ^ n < R := exists_pow_lt_of_lt_one R_pos (by norm_num : (1 : ℝ)/2 < 1), simp only [mem_Union, mem_Inter...
lemma
fderiv_measurable_aux.differentiable_set_subset_D
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "differentiable_at", "exists_pow_lt_of_lt_one", "fderiv", "pow_le_pow_of_le_one", "pow_pos" ]
Easy inclusion: a differentiability point with derivative in `K` belongs to `D f K`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
D_subset_differentiable_set {K : set (E →L[𝕜] F)} (hK : is_complete K) : D f K ⊆ {x | differentiable_at 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
begin have P : ∀ {n : ℕ}, (0 : ℝ) < (1/2) ^ n := pow_pos (by norm_num), rcases normed_field.exists_one_lt_norm 𝕜 with ⟨c, hc⟩, have cpos : 0 < ‖c‖ := lt_trans zero_lt_one hc, assume x hx, have : ∀ (e : ℕ), ∃ (n : ℕ), ∀ p q, n ≤ p → n ≤ q → ∃ L ∈ K, x ∈ A f L ((1/2) ^ p) ((1/2) ^ e) ∩ A f L ((1/2) ^ q) ((...
lemma
fderiv_measurable_aux.D_subset_differentiable_set
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "cauchy_seq", "cauchy_seq_tendsto_of_is_complete", "differentiable_at", "dist_comm", "dist_self", "div_nonneg", "div_pos", "exists_nat_pow_near_of_lt_one", "exists_pow_lt_of_lt_one", "fderiv", "ge_iff_le", "has_fderiv_at", "has_fderiv_at_iff_is_o_nhds_zero", "is_complete", "le_of_tendsto...
Harder inclusion: at a point in `D f K`, the function `f` has a derivative, in `K`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_set_eq_D (hK : is_complete K) : {x | differentiable_at 𝕜 f x ∧ fderiv 𝕜 f x ∈ K} = D f K
subset.antisymm (differentiable_set_subset_D _) (D_subset_differentiable_set hK)
theorem
fderiv_measurable_aux.differentiable_set_eq_D
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "differentiable_at", "fderiv", "is_complete" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measurable_set_of_differentiable_at_of_is_complete {K : set (E →L[𝕜] F)} (hK : is_complete K) : measurable_set {x | differentiable_at 𝕜 f x ∧ fderiv 𝕜 f x ∈ K}
by simp [differentiable_set_eq_D K hK, D, is_open_B.measurable_set, measurable_set.Inter, measurable_set.Union]
theorem
measurable_set_of_differentiable_at_of_is_complete
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "differentiable_at", "fderiv", "is_complete", "measurable_set", "measurable_set.Inter", "measurable_set.Union" ]
The set of differentiability points of a function, with derivative in a given complete set, is Borel-measurable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measurable_set_of_differentiable_at : measurable_set {x | differentiable_at 𝕜 f x}
begin have : is_complete (univ : set (E →L[𝕜] F)) := complete_univ, convert measurable_set_of_differentiable_at_of_is_complete 𝕜 f this, simp end
theorem
measurable_set_of_differentiable_at
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "complete_univ", "differentiable_at", "is_complete", "measurable_set", "measurable_set_of_differentiable_at_of_is_complete" ]
The set of differentiability points of a function taking values in a complete space is Borel-measurable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measurable_fderiv : measurable (fderiv 𝕜 f)
begin refine measurable_of_is_closed (λ s hs, _), have : fderiv 𝕜 f ⁻¹' s = {x | differentiable_at 𝕜 f x ∧ fderiv 𝕜 f x ∈ s} ∪ ({x | ¬differentiable_at 𝕜 f x} ∩ {x | (0 : E →L[𝕜] F) ∈ s}) := set.ext (λ x, mem_preimage.trans fderiv_mem_iff), rw this, exact (measurable_set_of_differentiable_at_of_is_...
lemma
measurable_fderiv
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "differentiable_at", "fderiv", "fderiv_mem_iff", "measurable", "measurable_of_is_closed", "measurable_set.const", "measurable_set_of_differentiable_at", "measurable_set_of_differentiable_at_of_is_complete", "set.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measurable_fderiv_apply_const [measurable_space F] [borel_space F] (y : E) : measurable (λ x, fderiv 𝕜 f x y)
(continuous_linear_map.measurable_apply y).comp (measurable_fderiv 𝕜 f)
lemma
measurable_fderiv_apply_const
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "borel_space", "continuous_linear_map.measurable_apply", "fderiv", "measurable", "measurable_fderiv", "measurable_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
measurable_deriv [measurable_space 𝕜] [opens_measurable_space 𝕜] [measurable_space F] [borel_space F] (f : 𝕜 → F) : measurable (deriv f)
by simpa only [fderiv_deriv] using measurable_fderiv_apply_const 𝕜 f 1
lemma
measurable_deriv
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "borel_space", "deriv", "fderiv_deriv", "measurable", "measurable_fderiv_apply_const", "measurable_space", "opens_measurable_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strongly_measurable_deriv [measurable_space 𝕜] [opens_measurable_space 𝕜] [second_countable_topology F] (f : 𝕜 → F) : strongly_measurable (deriv f)
by { borelize F, exact (measurable_deriv f).strongly_measurable }
lemma
strongly_measurable_deriv
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "deriv", "measurable_deriv", "measurable_space", "opens_measurable_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ae_measurable_deriv [measurable_space 𝕜] [opens_measurable_space 𝕜] [measurable_space F] [borel_space F] (f : 𝕜 → F) (μ : measure 𝕜) : ae_measurable (deriv f) μ
(measurable_deriv f).ae_measurable
lemma
ae_measurable_deriv
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "ae_measurable", "borel_space", "deriv", "measurable_deriv", "measurable_space", "opens_measurable_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ae_strongly_measurable_deriv [measurable_space 𝕜] [opens_measurable_space 𝕜] [second_countable_topology F] (f : 𝕜 → F) (μ : measure 𝕜) : ae_strongly_measurable (deriv f) μ
(strongly_measurable_deriv f).ae_strongly_measurable
lemma
ae_strongly_measurable_deriv
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "deriv", "measurable_space", "opens_measurable_space", "strongly_measurable_deriv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
A (f : ℝ → F) (L : F) (r ε : ℝ) : set ℝ
{x | ∃ r' ∈ Ioc (r/2) r, ∀ y z ∈ Icc x (x + r'), ‖f z - f y - (z-y) • L‖ ≤ ε * r}
def
right_deriv_measurable_aux.A
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[]
The set `A f L r ε` is the set of points `x` around which the function `f` is well approximated at scale `r` by the linear map `h ↦ h • L`, up to an error `ε`. We tweak the definition to make sure that this is open on the right.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
B (f : ℝ → F) (K : set F) (r s ε : ℝ) : set ℝ
⋃ (L ∈ K), (A f L r ε) ∩ (A f L s ε)
def
right_deriv_measurable_aux.B
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[]
The set `B f K r s ε` is the set of points `x` around which there exists a vector `L` belonging to `K` (a given set of vectors) such that `h • L` approximates well `f (x + h)` (up to an error `ε`), simultaneously at scales `r` and `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
D (f : ℝ → F) (K : set F) : set ℝ
⋂ (e : ℕ), ⋃ (n : ℕ), ⋂ (p ≥ n) (q ≥ n), B f K ((1/2) ^ p) ((1/2) ^ q) ((1/2) ^ e)
def
right_deriv_measurable_aux.D
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[]
The set `D f K` is a complicated set constructed using countable intersections and unions. Its main use is that, when `K` is complete, it is exactly the set of points where `f` is differentiable, with a derivative in `K`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
A_mem_nhds_within_Ioi {L : F} {r ε x : ℝ} (hx : x ∈ A f L r ε) : A f L r ε ∈ 𝓝[>] x
begin rcases hx with ⟨r', rr', hr'⟩, rw mem_nhds_within_Ioi_iff_exists_Ioo_subset, obtain ⟨s, s_gt, s_lt⟩ : ∃ (s : ℝ), r / 2 < s ∧ s < r' := exists_between rr'.1, have : s ∈ Ioc (r/2) r := ⟨s_gt, le_of_lt (s_lt.trans_le rr'.2)⟩, refine ⟨x + r' - s, by { simp only [mem_Ioi], linarith }, λ x' hx', ⟨s, this, _⟩⟩...
lemma
right_deriv_measurable_aux.A_mem_nhds_within_Ioi
analysis.calculus
src/analysis/calculus/fderiv_measurable.lean
[ "analysis.calculus.deriv.basic", "measure_theory.constructions.borel_space.continuous_linear_map", "measure_theory.function.strongly_measurable.basic" ]
[ "exists_between", "mem_nhds_within_Ioi_iff_exists_Ioo_subset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83