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iterated_fderiv_within_inter_open {n : ℕ} (hu : is_open u) (hx : x ∈ u) : iterated_fderiv_within 𝕜 n f (s ∩ u) x = iterated_fderiv_within 𝕜 n f s x
iterated_fderiv_within_inter (hu.mem_nhds hx)
lemma
iterated_fderiv_within_inter_open
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "is_open", "iterated_fderiv_within", "iterated_fderiv_within_inter" ]
The iterated differential within a set `s` at a point `x` is not modified if one intersects `s` with an open set containing `x`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_zero : cont_diff_on 𝕜 0 f s ↔ continuous_on f s
begin refine ⟨λ H, H.continuous_on, λ H, _⟩, assume x hx m hm, have : (m : ℕ∞) = 0 := le_antisymm hm bot_le, rw this, refine ⟨insert x s, self_mem_nhds_within, ftaylor_series_within 𝕜 f s, _⟩, rw has_ftaylor_series_up_to_on_zero_iff, exact ⟨by rwa insert_eq_of_mem hx, λ x hx, by simp [ftaylor_series_with...
lemma
cont_diff_on_zero
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "bot_le", "cont_diff_on", "continuous_on", "ftaylor_series_within", "has_ftaylor_series_up_to_on_zero_iff", "self_mem_nhds_within" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_within_at_zero (hx : x ∈ s) : cont_diff_within_at 𝕜 0 f s x ↔ ∃ u ∈ 𝓝[s] x, continuous_on f (s ∩ u)
begin split, { intros h, obtain ⟨u, H, p, hp⟩ := h 0 (by norm_num), refine ⟨u, _, _⟩, { simpa [hx] using H }, { simp only [with_top.coe_zero, has_ftaylor_series_up_to_on_zero_iff] at hp, exact hp.1.mono (inter_subset_right s u) } }, { rintros ⟨u, H, hu⟩, rw ← cont_diff_within_at_inter' H...
lemma
cont_diff_within_at_zero
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_within_at", "cont_diff_within_at_inter'", "continuous_on", "has_ftaylor_series_up_to_on_zero_iff", "mem_of_mem_nhds_within" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to_on.eq_ftaylor_series_of_unique_diff_on (h : has_ftaylor_series_up_to_on n f p s) {m : ℕ} (hmn : (m : ℕ∞) ≤ n) (hs : unique_diff_on 𝕜 s) (hx : x ∈ s) : p x m = iterated_fderiv_within 𝕜 m f s x
begin induction m with m IH generalizing x, { rw [h.zero_eq' hx, iterated_fderiv_within_zero_eq_comp] }, { have A : (m : ℕ∞) < n := lt_of_lt_of_le (with_top.coe_lt_coe.2 (lt_add_one m)) hmn, have : has_fderiv_within_at (λ (y : E), iterated_fderiv_within 𝕜 m f s y) (continuous_multilinear_map.curry_left...
theorem
has_ftaylor_series_up_to_on.eq_ftaylor_series_of_unique_diff_on
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_multilinear_map.curry_left", "continuous_multilinear_map.uncurry_curry_left", "function.comp_apply", "has_fderiv_within_at", "has_ftaylor_series_up_to_on", "iterated_fderiv_within", "iterated_fderiv_within_succ_eq_comp_left", "iterated_fderiv_within_zero_eq_comp", "lt_add_one", "unique...
On a set with unique differentiability, any choice of iterated differential has to coincide with the one we have chosen in `iterated_fderiv_within 𝕜 m f s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on.ftaylor_series_within (h : cont_diff_on 𝕜 n f s) (hs : unique_diff_on 𝕜 s) : has_ftaylor_series_up_to_on n f (ftaylor_series_within 𝕜 f s) s
begin split, { assume x hx, simp only [ftaylor_series_within, continuous_multilinear_map.uncurry0_apply, iterated_fderiv_within_zero_apply] }, { assume m hm x hx, rcases (h x hx) m.succ (enat.add_one_le_of_lt hm) with ⟨u, hu, p, Hp⟩, rw insert_eq_of_mem hx at hu, rcases mem_nhds_wit...
theorem
cont_diff_on.ftaylor_series_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont", "cont_diff_on", "continuous_multilinear_map.uncurry0_apply", "continuous_on_of_locally_continuous_on", "enat.add_one_le_of_lt", "fderiv_within", "ftaylor_series_within", "has_fderiv_within_at_inter", "has_ftaylor_series_up_to_on", "is_open.mem_nhds", "iterated_fderiv_within", "iterated...
When a function is `C^n` in a set `s` of unique differentiability, it admits `ftaylor_series_within 𝕜 f s` as a Taylor series up to order `n` in `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_of_continuous_on_differentiable_on (Hcont : ∀ (m : ℕ), (m : ℕ∞) ≤ n → continuous_on (λ x, iterated_fderiv_within 𝕜 m f s x) s) (Hdiff : ∀ (m : ℕ), (m : ℕ∞) < n → differentiable_on 𝕜 (λ x, iterated_fderiv_within 𝕜 m f s x) s) : cont_diff_on 𝕜 n f s
begin assume x hx m hm, rw insert_eq_of_mem hx, refine ⟨s, self_mem_nhds_within, ftaylor_series_within 𝕜 f s, _⟩, split, { assume y hy, simp only [ftaylor_series_within, continuous_multilinear_map.uncurry0_apply, iterated_fderiv_within_zero_apply] }, { assume k hk y hy, convert (Hdi...
lemma
cont_diff_on_of_continuous_on_differentiable_on
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "coe_fn_coe_base", "cont_diff_on", "continuous_linear_equiv.coe_apply", "continuous_linear_map.curry_uncurry_left", "continuous_multilinear_map.uncurry0_apply", "continuous_on", "differentiable_on", "ftaylor_series_within", "has_fderiv_within_at", "iterated_fderiv_within", "iterated_fderiv_withi...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_of_differentiable_on (h : ∀(m : ℕ), (m : ℕ∞) ≤ n → differentiable_on 𝕜 (iterated_fderiv_within 𝕜 m f s) s) : cont_diff_on 𝕜 n f s
cont_diff_on_of_continuous_on_differentiable_on (λ m hm, (h m hm).continuous_on) (λ m hm, (h m (le_of_lt hm)))
lemma
cont_diff_on_of_differentiable_on
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_of_continuous_on_differentiable_on", "continuous_on", "differentiable_on", "iterated_fderiv_within" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on.continuous_on_iterated_fderiv_within {m : ℕ} (h : cont_diff_on 𝕜 n f s) (hmn : (m : ℕ∞) ≤ n) (hs : unique_diff_on 𝕜 s) : continuous_on (iterated_fderiv_within 𝕜 m f s) s
(h.ftaylor_series_within hs).cont m hmn
lemma
cont_diff_on.continuous_on_iterated_fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont", "cont_diff_on", "continuous_on", "iterated_fderiv_within", "unique_diff_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on.differentiable_on_iterated_fderiv_within {m : ℕ} (h : cont_diff_on 𝕜 n f s) (hmn : (m : ℕ∞) < n) (hs : unique_diff_on 𝕜 s) : differentiable_on 𝕜 (iterated_fderiv_within 𝕜 m f s) s
λ x hx, ((h.ftaylor_series_within hs).fderiv_within m hmn x hx).differentiable_within_at
lemma
cont_diff_on.differentiable_on_iterated_fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "differentiable_on", "differentiable_within_at", "fderiv_within", "iterated_fderiv_within", "unique_diff_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_within_at.differentiable_within_at_iterated_fderiv_within {m : ℕ} (h : cont_diff_within_at 𝕜 n f s x) (hmn : (m : ℕ∞) < n) (hs : unique_diff_on 𝕜 (insert x s)) : differentiable_within_at 𝕜 (iterated_fderiv_within 𝕜 m f s) s x
begin rcases h.cont_diff_on' (enat.add_one_le_of_lt hmn) with ⟨u, uo, xu, hu⟩, set t := insert x s ∩ u, have A : t =ᶠ[𝓝[≠] x] s, { simp only [set_eventually_eq_iff_inf_principal, ← nhds_within_inter'], rw [← inter_assoc, nhds_within_inter_of_mem', ← diff_eq_compl_inter, insert_diff_of_mem, diff_eq_co...
lemma
cont_diff_within_at.differentiable_within_at_iterated_fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_within_at", "differentiable_within_at", "differentiable_within_at_congr_set'", "enat.add_one_le_of_lt", "inf_le_left", "iterated_fderiv_within", "iterated_fderiv_within_eventually_congr_set'", "mem_nhds_within_of_mem_nhds", "nhds_within_inter'", "nhds_within_inter_of_mem'", "unique_di...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_iff_continuous_on_differentiable_on (hs : unique_diff_on 𝕜 s) : cont_diff_on 𝕜 n f s ↔ (∀ (m : ℕ), (m : ℕ∞) ≤ n → continuous_on (λ x, iterated_fderiv_within 𝕜 m f s x) s) ∧ (∀ (m : ℕ), (m : ℕ∞) < n → differentiable_on 𝕜 (λ x, iterated_fderiv_within 𝕜 m f s x) s)
⟨λ h, ⟨λ m hm, h.continuous_on_iterated_fderiv_within hm hs, λ m hm, h.differentiable_on_iterated_fderiv_within hm hs⟩, λ h, cont_diff_on_of_continuous_on_differentiable_on h.1 h.2⟩
lemma
cont_diff_on_iff_continuous_on_differentiable_on
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_of_continuous_on_differentiable_on", "continuous_on", "differentiable_on", "iterated_fderiv_within", "unique_diff_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_succ_of_fderiv_within {n : ℕ} (hf : differentiable_on 𝕜 f s) (h : cont_diff_on 𝕜 n (λ y, fderiv_within 𝕜 f s y) s) : cont_diff_on 𝕜 ((n + 1) : ℕ) f s
begin intros x hx, rw [cont_diff_within_at_succ_iff_has_fderiv_within_at, insert_eq_of_mem hx], exact ⟨s, self_mem_nhds_within, fderiv_within 𝕜 f s, λ y hy, (hf y hy).has_fderiv_within_at, h x hx⟩ end
lemma
cont_diff_on_succ_of_fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_within_at_succ_iff_has_fderiv_within_at", "differentiable_on", "fderiv_within", "has_fderiv_within_at", "self_mem_nhds_within" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_succ_iff_fderiv_within {n : ℕ} (hs : unique_diff_on 𝕜 s) : cont_diff_on 𝕜 ((n + 1) : ℕ) f s ↔ differentiable_on 𝕜 f s ∧ cont_diff_on 𝕜 n (λ y, fderiv_within 𝕜 f s y) s
begin refine ⟨λ H, _, λ h, cont_diff_on_succ_of_fderiv_within h.1 h.2⟩, refine ⟨H.differentiable_on (with_top.coe_le_coe.2 (nat.le_add_left 1 n)), λ x hx, _⟩, rcases cont_diff_within_at_succ_iff_has_fderiv_within_at.1 (H x hx) with ⟨u, hu, f', hff', hf'⟩, rcases mem_nhds_within.1 hu with ⟨o, o_open, xo, ho⟩...
theorem
cont_diff_on_succ_iff_fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_succ_of_fderiv_within", "cont_diff_within_at_inter'", "differentiable_on", "fderiv_within", "fderiv_within_inter", "filter.eventually_eq_of_mem", "is_open.mem_nhds", "mem_nhds_within_of_mem_nhds", "unique_diff_on" ]
A function is `C^(n + 1)` on a domain with unique derivatives if and only if it is differentiable there, and its derivative (expressed with `fderiv_within`) is `C^n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_succ_iff_has_fderiv_within {n : ℕ} (hs : unique_diff_on 𝕜 s) : cont_diff_on 𝕜 ((n + 1) : ℕ) f s ↔ ∃ (f' : E → (E →L[𝕜] F)), cont_diff_on 𝕜 n f' s ∧ ∀ x, x ∈ s → has_fderiv_within_at f (f' x) s x
begin rw cont_diff_on_succ_iff_fderiv_within hs, refine ⟨λ h, ⟨fderiv_within 𝕜 f s, h.2, λ x hx, (h.1 x hx).has_fderiv_within_at⟩, λ h, _⟩, rcases h with ⟨f', h1, h2⟩, refine ⟨λ x hx, (h2 x hx).differentiable_within_at, λ x hx, _⟩, exact (h1 x hx).congr' (λ y hy, (h2 y hy).fderiv_within (hs y hy)) hx, end
lemma
cont_diff_on_succ_iff_has_fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_succ_iff_fderiv_within", "differentiable_within_at", "fderiv_within", "has_fderiv_within_at", "unique_diff_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_succ_iff_fderiv_of_open {n : ℕ} (hs : is_open s) : cont_diff_on 𝕜 ((n + 1) : ℕ) f s ↔ differentiable_on 𝕜 f s ∧ cont_diff_on 𝕜 n (λ y, fderiv 𝕜 f y) s
begin rw cont_diff_on_succ_iff_fderiv_within hs.unique_diff_on, congrm _ ∧ _, apply cont_diff_on_congr, assume x hx, exact fderiv_within_of_open hs hx end
theorem
cont_diff_on_succ_iff_fderiv_of_open
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_congr", "cont_diff_on_succ_iff_fderiv_within", "differentiable_on", "fderiv", "fderiv_within_of_open", "is_open" ]
A function is `C^(n + 1)` on an open domain if and only if it is differentiable there, and its derivative (expressed with `fderiv`) is `C^n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_top_iff_fderiv_within (hs : unique_diff_on 𝕜 s) : cont_diff_on 𝕜 ∞ f s ↔ differentiable_on 𝕜 f s ∧ cont_diff_on 𝕜 ∞ (λ y, fderiv_within 𝕜 f s y) s
begin split, { assume h, refine ⟨h.differentiable_on le_top, _⟩, apply cont_diff_on_top.2 (λ n, ((cont_diff_on_succ_iff_fderiv_within hs).1 _).2), exact h.of_le le_top }, { assume h, refine cont_diff_on_top.2 (λ n, _), have A : (n : ℕ∞) ≤ ∞ := le_top, apply ((cont_diff_on_succ_iff_fderiv_w...
theorem
cont_diff_on_top_iff_fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_succ_iff_fderiv_within", "differentiable_on", "fderiv_within", "le_top", "unique_diff_on" ]
A function is `C^∞` on a domain with unique derivatives if and only if it is differentiable there, and its derivative (expressed with `fderiv_within`) is `C^∞`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_top_iff_fderiv_of_open (hs : is_open s) : cont_diff_on 𝕜 ∞ f s ↔ differentiable_on 𝕜 f s ∧ cont_diff_on 𝕜 ∞ (λ y, fderiv 𝕜 f y) s
begin rw cont_diff_on_top_iff_fderiv_within hs.unique_diff_on, congrm _ ∧ _, apply cont_diff_on_congr, assume x hx, exact fderiv_within_of_open hs hx end
theorem
cont_diff_on_top_iff_fderiv_of_open
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_congr", "cont_diff_on_top_iff_fderiv_within", "differentiable_on", "fderiv", "fderiv_within_of_open", "is_open" ]
A function is `C^∞` on an open domain if and only if it is differentiable there, and its derivative (expressed with `fderiv`) is `C^∞`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on.fderiv_within (hf : cont_diff_on 𝕜 n f s) (hs : unique_diff_on 𝕜 s) (hmn : m + 1 ≤ n) : cont_diff_on 𝕜 m (λ y, fderiv_within 𝕜 f s y) s
begin cases m, { change ∞ + 1 ≤ n at hmn, have : n = ∞, by simpa using hmn, rw this at hf, exact ((cont_diff_on_top_iff_fderiv_within hs).1 hf).2 }, { change (m.succ : ℕ∞) ≤ n at hmn, exact ((cont_diff_on_succ_iff_fderiv_within hs).1 (hf.of_le hmn)).2 } end
lemma
cont_diff_on.fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_succ_iff_fderiv_within", "cont_diff_on_top_iff_fderiv_within", "fderiv_within", "unique_diff_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on.fderiv_of_open (hf : cont_diff_on 𝕜 n f s) (hs : is_open s) (hmn : m + 1 ≤ n) : cont_diff_on 𝕜 m (λ y, fderiv 𝕜 f y) s
(hf.fderiv_within hs.unique_diff_on hmn).congr (λ x hx, (fderiv_within_of_open hs hx).symm)
lemma
cont_diff_on.fderiv_of_open
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "fderiv", "fderiv_within_of_open", "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on.continuous_on_fderiv_within (h : cont_diff_on 𝕜 n f s) (hs : unique_diff_on 𝕜 s) (hn : 1 ≤ n) : continuous_on (λ x, fderiv_within 𝕜 f s x) s
((cont_diff_on_succ_iff_fderiv_within hs).1 (h.of_le hn)).2.continuous_on
lemma
cont_diff_on.continuous_on_fderiv_within
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_succ_iff_fderiv_within", "continuous_on", "fderiv_within", "unique_diff_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on.continuous_on_fderiv_of_open (h : cont_diff_on 𝕜 n f s) (hs : is_open s) (hn : 1 ≤ n) : continuous_on (λ x, fderiv 𝕜 f x) s
((cont_diff_on_succ_iff_fderiv_of_open hs).1 (h.of_le hn)).2.continuous_on
lemma
cont_diff_on.continuous_on_fderiv_of_open
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_on", "cont_diff_on_succ_iff_fderiv_of_open", "continuous_on", "fderiv", "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to (n : ℕ∞) (f : E → F) (p : E → formal_multilinear_series 𝕜 E F) : Prop
(zero_eq : ∀ x, (p x 0).uncurry0 = f x) (fderiv : ∀ (m : ℕ) (hm : (m : ℕ∞) < n), ∀ x, has_fderiv_at (λ y, p y m) (p x m.succ).curry_left x) (cont : ∀ (m : ℕ) (hm : (m : ℕ∞) ≤ n), continuous (λ x, p x m))
structure
has_ftaylor_series_up_to
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont", "continuous", "fderiv", "formal_multilinear_series", "has_fderiv_at" ]
`has_ftaylor_series_up_to n f p` registers the fact that `p 0 = f` and `p (m+1)` is a derivative of `p m` for `m < n`, and is continuous for `m ≤ n`. This is a predicate analogous to `has_fderiv_at` but for higher order derivatives.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to.zero_eq' (h : has_ftaylor_series_up_to n f p) (x : E) : p x 0 = (continuous_multilinear_curry_fin0 𝕜 E F).symm (f x)
by { rw ← h.zero_eq x, symmetry, exact continuous_multilinear_map.uncurry0_curry0 _ }
lemma
has_ftaylor_series_up_to.zero_eq'
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_multilinear_curry_fin0", "continuous_multilinear_map.uncurry0_curry0", "has_ftaylor_series_up_to" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to_on_univ_iff : has_ftaylor_series_up_to_on n f p univ ↔ has_ftaylor_series_up_to n f p
begin split, { assume H, split, { exact λ x, H.zero_eq x (mem_univ x) }, { assume m hm x, rw ← has_fderiv_within_at_univ, exact H.fderiv_within m hm x (mem_univ x) }, { assume m hm, rw continuous_iff_continuous_on_univ, exact H.cont m hm } }, { assume H, split, { ex...
lemma
has_ftaylor_series_up_to_on_univ_iff
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_iff_continuous_on_univ", "has_fderiv_within_at_univ", "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to.has_ftaylor_series_up_to_on (h : has_ftaylor_series_up_to n f p) (s : set E) : has_ftaylor_series_up_to_on n f p s
(has_ftaylor_series_up_to_on_univ_iff.2 h).mono (subset_univ _)
lemma
has_ftaylor_series_up_to.has_ftaylor_series_up_to_on
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to.of_le (h : has_ftaylor_series_up_to n f p) (hmn : m ≤ n) : has_ftaylor_series_up_to m f p
by { rw ← has_ftaylor_series_up_to_on_univ_iff at h ⊢, exact h.of_le hmn }
lemma
has_ftaylor_series_up_to.of_le
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on_univ_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to.continuous (h : has_ftaylor_series_up_to n f p) : continuous f
begin rw ← has_ftaylor_series_up_to_on_univ_iff at h, rw continuous_iff_continuous_on_univ, exact h.continuous_on end
lemma
has_ftaylor_series_up_to.continuous
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous", "continuous_iff_continuous_on_univ", "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on_univ_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to_zero_iff : has_ftaylor_series_up_to 0 f p ↔ continuous f ∧ (∀ x, (p x 0).uncurry0 = f x)
by simp [has_ftaylor_series_up_to_on_univ_iff.symm, continuous_iff_continuous_on_univ, has_ftaylor_series_up_to_on_zero_iff]
lemma
has_ftaylor_series_up_to_zero_iff
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous", "continuous_iff_continuous_on_univ", "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on_zero_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to_top_iff : has_ftaylor_series_up_to ∞ f p ↔ ∀ (n : ℕ), has_ftaylor_series_up_to n f p
by simp only [← has_ftaylor_series_up_to_on_univ_iff, has_ftaylor_series_up_to_on_top_iff]
lemma
has_ftaylor_series_up_to_top_iff
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on_top_iff", "has_ftaylor_series_up_to_on_univ_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to_top_iff' : has_ftaylor_series_up_to ∞ f p ↔ (∀ x, (p x 0).uncurry0 = f x) ∧ (∀ (m : ℕ) x, has_fderiv_at (λ y, p y m) (p x m.succ).curry_left x)
by simp only [← has_ftaylor_series_up_to_on_univ_iff, has_ftaylor_series_up_to_on_top_iff', mem_univ, forall_true_left, has_fderiv_within_at_univ]
lemma
has_ftaylor_series_up_to_top_iff'
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "forall_true_left", "has_fderiv_at", "has_fderiv_within_at_univ", "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on_top_iff'", "has_ftaylor_series_up_to_on_univ_iff" ]
In the case that `n = ∞` we don't need the continuity assumption in `has_ftaylor_series_up_to`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to.has_fderiv_at (h : has_ftaylor_series_up_to n f p) (hn : 1 ≤ n) (x : E) : has_fderiv_at f (continuous_multilinear_curry_fin1 𝕜 E F (p x 1)) x
begin rw [← has_fderiv_within_at_univ], exact (has_ftaylor_series_up_to_on_univ_iff.2 h).has_fderiv_within_at hn (mem_univ _) end
lemma
has_ftaylor_series_up_to.has_fderiv_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_multilinear_curry_fin1", "has_fderiv_at", "has_fderiv_within_at", "has_fderiv_within_at_univ", "has_ftaylor_series_up_to" ]
If a function has a Taylor series at order at least `1`, then the term of order `1` of this series is a derivative of `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to.differentiable (h : has_ftaylor_series_up_to n f p) (hn : 1 ≤ n) : differentiable 𝕜 f
λ x, (h.has_fderiv_at hn x).differentiable_at
lemma
has_ftaylor_series_up_to.differentiable
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "differentiable", "differentiable_at", "has_ftaylor_series_up_to" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to_succ_iff_right {n : ℕ} : has_ftaylor_series_up_to ((n + 1) : ℕ) f p ↔ (∀ x, (p x 0).uncurry0 = f x) ∧ (∀ x, has_fderiv_at (λ y, p y 0) (p x 1).curry_left x) ∧ has_ftaylor_series_up_to n (λ x, continuous_multilinear_curry_fin1 𝕜 E F (p x 1)) (λ x, (p x).shift)
by simp only [has_ftaylor_series_up_to_on_succ_iff_right, ← has_ftaylor_series_up_to_on_univ_iff, mem_univ, forall_true_left, has_fderiv_within_at_univ]
theorem
has_ftaylor_series_up_to_succ_iff_right
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_multilinear_curry_fin1", "forall_true_left", "has_fderiv_at", "has_fderiv_within_at_univ", "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on_succ_iff_right", "has_ftaylor_series_up_to_on_univ_iff" ]
`p` is a Taylor series of `f` up to `n+1` if and only if `p.shift` is a Taylor series up to `n` for `p 1`, which is a derivative of `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at (n : ℕ∞) (f : E → F) (x : E) : Prop
cont_diff_within_at 𝕜 n f univ x
def
cont_diff_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_within_at" ]
A function is continuously differentiable up to `n` at a point `x` if, for any integer `k ≤ n`, there is a neighborhood of `x` where `f` admits derivatives up to order `n`, which are continuous.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_within_at_univ : cont_diff_within_at 𝕜 n f univ x ↔ cont_diff_at 𝕜 n f x
iff.rfl
theorem
cont_diff_within_at_univ
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "cont_diff_within_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at_top : cont_diff_at 𝕜 ∞ f x ↔ ∀ (n : ℕ), cont_diff_at 𝕜 n f x
by simp [← cont_diff_within_at_univ, cont_diff_within_at_top]
lemma
cont_diff_at_top
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "cont_diff_within_at_top", "cont_diff_within_at_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at.cont_diff_within_at (h : cont_diff_at 𝕜 n f x) : cont_diff_within_at 𝕜 n f s x
h.mono (subset_univ _)
lemma
cont_diff_at.cont_diff_within_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "cont_diff_within_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_within_at.cont_diff_at (h : cont_diff_within_at 𝕜 n f s x) (hx : s ∈ 𝓝 x) : cont_diff_at 𝕜 n f x
by rwa [cont_diff_at, ← cont_diff_within_at_inter hx, univ_inter]
lemma
cont_diff_within_at.cont_diff_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "cont_diff_within_at", "cont_diff_within_at_inter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at.congr_of_eventually_eq (h : cont_diff_at 𝕜 n f x) (hg : f₁ =ᶠ[𝓝 x] f) : cont_diff_at 𝕜 n f₁ x
h.congr_of_eventually_eq' (by rwa nhds_within_univ) (mem_univ x)
lemma
cont_diff_at.congr_of_eventually_eq
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "nhds_within_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at.of_le (h : cont_diff_at 𝕜 n f x) (hmn : m ≤ n) : cont_diff_at 𝕜 m f x
h.of_le hmn
lemma
cont_diff_at.of_le
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at.continuous_at (h : cont_diff_at 𝕜 n f x) : continuous_at f x
by simpa [continuous_within_at_univ] using h.continuous_within_at
lemma
cont_diff_at.continuous_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "continuous_at", "continuous_within_at_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at.differentiable_at (h : cont_diff_at 𝕜 n f x) (hn : 1 ≤ n) : differentiable_at 𝕜 f x
by simpa [hn, differentiable_within_at_univ] using h.differentiable_within_at
lemma
cont_diff_at.differentiable_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "differentiable_at", "differentiable_within_at_univ" ]
If a function is `C^n` with `n ≥ 1` at a point, then it is differentiable there.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at_succ_iff_has_fderiv_at {n : ℕ} : cont_diff_at 𝕜 ((n + 1) : ℕ) f x ↔ (∃ f' : E → E →L[𝕜] F, (∃ u ∈ 𝓝 x, ∀ x ∈ u, has_fderiv_at f (f' x) x) ∧ cont_diff_at 𝕜 n f' x)
begin rw [← cont_diff_within_at_univ, cont_diff_within_at_succ_iff_has_fderiv_within_at], simp only [nhds_within_univ, exists_prop, mem_univ, insert_eq_of_mem], split, { rintros ⟨u, H, f', h_fderiv, h_cont_diff⟩, rcases mem_nhds_iff.mp H with ⟨t, htu, ht, hxt⟩, refine ⟨f', ⟨t, _⟩, h_cont_diff.cont_diff_...
theorem
cont_diff_at_succ_iff_has_fderiv_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "cont_diff_within_at_succ_iff_has_fderiv_within_at", "cont_diff_within_at_univ", "exists_prop", "has_fderiv_at", "has_fderiv_within_at", "nhds_within_univ" ]
A function is `C^(n + 1)` at a point iff locally, it has a derivative which is `C^n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at.eventually {n : ℕ} (h : cont_diff_at 𝕜 n f x) : ∀ᶠ y in 𝓝 x, cont_diff_at 𝕜 n f y
by simpa [nhds_within_univ] using h.eventually
theorem
cont_diff_at.eventually
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "nhds_within_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff (n : ℕ∞) (f : E → F) : Prop
∃ p : E → formal_multilinear_series 𝕜 E F, has_ftaylor_series_up_to n f p
def
cont_diff
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "formal_multilinear_series", "has_ftaylor_series_up_to" ]
A function is continuously differentiable up to `n` if it admits derivatives up to order `n`, which are continuous. Contrary to the case of definitions in domains (where derivatives might not be unique) we do not need to localize the definition in space or time.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_ftaylor_series_up_to.cont_diff {f' : E → formal_multilinear_series 𝕜 E F} (hf : has_ftaylor_series_up_to n f f') : cont_diff 𝕜 n f
⟨f', hf⟩
lemma
has_ftaylor_series_up_to.cont_diff
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "formal_multilinear_series", "has_ftaylor_series_up_to" ]
If `f` has a Taylor series up to `n`, then it is `C^n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_on_univ : cont_diff_on 𝕜 n f univ ↔ cont_diff 𝕜 n f
begin split, { assume H, use ftaylor_series_within 𝕜 f univ, rw ← has_ftaylor_series_up_to_on_univ_iff, exact H.ftaylor_series_within unique_diff_on_univ }, { rintros ⟨p, hp⟩ x hx m hm, exact ⟨univ, filter.univ_sets _, p, (hp.has_ftaylor_series_up_to_on univ).of_le hm⟩ } end
theorem
cont_diff_on_univ
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on", "ftaylor_series_within", "has_ftaylor_series_up_to_on_univ_iff", "unique_diff_on_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_iff_cont_diff_at : cont_diff 𝕜 n f ↔ ∀ x, cont_diff_at 𝕜 n f x
by simp [← cont_diff_on_univ, cont_diff_on, cont_diff_at]
lemma
cont_diff_iff_cont_diff_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_at", "cont_diff_on", "cont_diff_on_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.cont_diff_at (h : cont_diff 𝕜 n f) : cont_diff_at 𝕜 n f x
cont_diff_iff_cont_diff_at.1 h x
lemma
cont_diff.cont_diff_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.cont_diff_within_at (h : cont_diff 𝕜 n f) : cont_diff_within_at 𝕜 n f s x
h.cont_diff_at.cont_diff_within_at
lemma
cont_diff.cont_diff_within_at
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_within_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_top : cont_diff 𝕜 ∞ f ↔ ∀ (n : ℕ), cont_diff 𝕜 n f
by simp [cont_diff_on_univ.symm, cont_diff_on_top]
lemma
cont_diff_top
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_all_iff_nat : (∀ n, cont_diff 𝕜 n f) ↔ (∀ n : ℕ, cont_diff 𝕜 n f)
by simp only [← cont_diff_on_univ, cont_diff_on_all_iff_nat]
lemma
cont_diff_all_iff_nat
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on_all_iff_nat", "cont_diff_on_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.cont_diff_on (h : cont_diff 𝕜 n f) : cont_diff_on 𝕜 n f s
(cont_diff_on_univ.2 h).mono (subset_univ _)
lemma
cont_diff.cont_diff_on
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_zero : cont_diff 𝕜 0 f ↔ continuous f
begin rw [← cont_diff_on_univ, continuous_iff_continuous_on_univ], exact cont_diff_on_zero end
lemma
cont_diff_zero
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on_univ", "cont_diff_on_zero", "continuous", "continuous_iff_continuous_on_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at_zero : cont_diff_at 𝕜 0 f x ↔ ∃ u ∈ 𝓝 x, continuous_on f u
by { rw ← cont_diff_within_at_univ, simp [cont_diff_within_at_zero, nhds_within_univ] }
lemma
cont_diff_at_zero
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff_at", "cont_diff_within_at_univ", "cont_diff_within_at_zero", "continuous_on", "nhds_within_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_at_one_iff : cont_diff_at 𝕜 1 f x ↔ ∃ f' : E → (E →L[𝕜] F), ∃ u ∈ 𝓝 x, continuous_on f' u ∧ ∀ x ∈ u, has_fderiv_at f (f' x) x
by simp_rw [show (1 : ℕ∞) = (0 + 1 : ℕ), from (zero_add 1).symm, cont_diff_at_succ_iff_has_fderiv_at, show ((0 : ℕ) : ℕ∞) = 0, from rfl, cont_diff_at_zero, exists_mem_and_iff antitone_bforall antitone_continuous_on, and_comm]
theorem
cont_diff_at_one_iff
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "antitone_continuous_on", "cont_diff_at", "cont_diff_at_succ_iff_has_fderiv_at", "cont_diff_at_zero", "continuous_on", "has_fderiv_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.of_le (h : cont_diff 𝕜 n f) (hmn : m ≤ n) : cont_diff 𝕜 m f
cont_diff_on_univ.1 $ (cont_diff_on_univ.2 h).of_le hmn
lemma
cont_diff.of_le
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.of_succ {n : ℕ} (h : cont_diff 𝕜 (n + 1) f) : cont_diff 𝕜 n f
h.of_le $ with_top.coe_le_coe.mpr le_self_add
lemma
cont_diff.of_succ
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.one_of_succ {n : ℕ} (h : cont_diff 𝕜 (n + 1) f) : cont_diff 𝕜 1 f
h.of_le $ with_top.coe_le_coe.mpr le_add_self
lemma
cont_diff.one_of_succ
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.continuous (h : cont_diff 𝕜 n f) : continuous f
cont_diff_zero.1 (h.of_le bot_le)
lemma
cont_diff.continuous
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "bot_le", "cont_diff", "continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.differentiable (h : cont_diff 𝕜 n f) (hn : 1 ≤ n) : differentiable 𝕜 f
differentiable_on_univ.1 $ (cont_diff_on_univ.2 h).differentiable_on hn
lemma
cont_diff.differentiable
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "differentiable", "differentiable_on" ]
If a function is `C^n` with `n ≥ 1`, then it is differentiable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_iff_forall_nat_le : cont_diff 𝕜 n f ↔ ∀ m : ℕ, ↑m ≤ n → cont_diff 𝕜 m f
by { simp_rw [← cont_diff_on_univ], exact cont_diff_on_iff_forall_nat_le }
lemma
cont_diff_iff_forall_nat_le
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on_iff_forall_nat_le", "cont_diff_on_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_succ_iff_has_fderiv {n : ℕ} : cont_diff 𝕜 ((n + 1) : ℕ) f ↔ ∃ (f' : E → (E →L[𝕜] F)), cont_diff 𝕜 n f' ∧ ∀ x, has_fderiv_at f (f' x) x
by simp only [← cont_diff_on_univ, ← has_fderiv_within_at_univ, cont_diff_on_succ_iff_has_fderiv_within (unique_diff_on_univ), set.mem_univ, forall_true_left]
lemma
cont_diff_succ_iff_has_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on_succ_iff_has_fderiv_within", "cont_diff_on_univ", "forall_true_left", "has_fderiv_at", "has_fderiv_within_at_univ", "set.mem_univ", "unique_diff_on_univ" ]
A function is `C^(n+1)` iff it has a `C^n` derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv (n : ℕ) (f : E → F) : E → (E [×n]→L[𝕜] F)
nat.rec_on n (λ x, continuous_multilinear_map.curry0 𝕜 E (f x)) (λ n rec x, continuous_linear_map.uncurry_left (fderiv 𝕜 rec x))
def
iterated_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_linear_map.uncurry_left", "continuous_multilinear_map.curry0", "fderiv" ]
The `n`-th derivative of a function, as a multilinear map, defined inductively.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ftaylor_series (f : E → F) (x : E) : formal_multilinear_series 𝕜 E F
λ n, iterated_fderiv 𝕜 n f x
def
ftaylor_series
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "formal_multilinear_series", "iterated_fderiv" ]
Formal Taylor series associated to a function within a set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_zero_apply (m : (fin 0) → E) : (iterated_fderiv 𝕜 0 f x : ((fin 0) → E) → F) m = f x
rfl
lemma
iterated_fderiv_zero_apply
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "iterated_fderiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_zero_eq_comp : iterated_fderiv 𝕜 0 f = (continuous_multilinear_curry_fin0 𝕜 E F).symm ∘ f
rfl
lemma
iterated_fderiv_zero_eq_comp
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_multilinear_curry_fin0", "iterated_fderiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_iterated_fderiv_zero : ‖iterated_fderiv 𝕜 0 f x‖ = ‖f x‖
by rw [iterated_fderiv_zero_eq_comp, linear_isometry_equiv.norm_map]
lemma
norm_iterated_fderiv_zero
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "iterated_fderiv_zero_eq_comp", "linear_isometry_equiv.norm_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_with_zero_eq : iterated_fderiv_within 𝕜 0 f s = iterated_fderiv 𝕜 0 f
by { ext, refl }
lemma
iterated_fderiv_with_zero_eq
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "iterated_fderiv", "iterated_fderiv_within" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_succ_apply_left {n : ℕ} (m : fin (n + 1) → E): (iterated_fderiv 𝕜 (n + 1) f x : (fin (n + 1) → E) → F) m = (fderiv 𝕜 (iterated_fderiv 𝕜 n f) x : E → (E [×n]→L[𝕜] F)) (m 0) (tail m)
rfl
lemma
iterated_fderiv_succ_apply_left
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "fderiv", "iterated_fderiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_succ_eq_comp_left {n : ℕ} : iterated_fderiv 𝕜 (n + 1) f = (continuous_multilinear_curry_left_equiv 𝕜 (λ (i : fin (n + 1)), E) F) ∘ (fderiv 𝕜 (iterated_fderiv 𝕜 n f))
rfl
lemma
iterated_fderiv_succ_eq_comp_left
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_multilinear_curry_left_equiv", "fderiv", "iterated_fderiv" ]
Writing explicitly the `n+1`-th derivative as the composition of a currying linear equiv, and the derivative of the `n`-th derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fderiv_iterated_fderiv {n : ℕ} : fderiv 𝕜 (iterated_fderiv 𝕜 n f) = (continuous_multilinear_curry_left_equiv 𝕜 (λ (i : fin (n + 1)), E) F).symm ∘ (iterated_fderiv 𝕜 (n + 1) f)
begin rw iterated_fderiv_succ_eq_comp_left, ext1 x, simp only [function.comp_app, linear_isometry_equiv.symm_apply_apply], end
lemma
fderiv_iterated_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_multilinear_curry_left_equiv", "fderiv", "iterated_fderiv", "iterated_fderiv_succ_eq_comp_left", "linear_isometry_equiv.symm_apply_apply" ]
Writing explicitly the derivative of the `n`-th derivative as the composition of a currying linear equiv, and the `n + 1`-th derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_compact_support.iterated_fderiv (hf : has_compact_support f) (n : ℕ) : has_compact_support (iterated_fderiv 𝕜 n f)
begin induction n with n IH, { rw [iterated_fderiv_zero_eq_comp], apply hf.comp_left, exact linear_isometry_equiv.map_zero _ }, { rw iterated_fderiv_succ_eq_comp_left, apply (IH.fderiv 𝕜).comp_left, exact linear_isometry_equiv.map_zero _ } end
lemma
has_compact_support.iterated_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "iterated_fderiv", "iterated_fderiv_succ_eq_comp_left", "iterated_fderiv_zero_eq_comp", "linear_isometry_equiv.map_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_fderiv_iterated_fderiv {n : ℕ} : ‖fderiv 𝕜 (iterated_fderiv 𝕜 n f) x‖ = ‖iterated_fderiv 𝕜 (n + 1) f x‖
by rw [iterated_fderiv_succ_eq_comp_left, linear_isometry_equiv.norm_map]
lemma
norm_fderiv_iterated_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "iterated_fderiv", "iterated_fderiv_succ_eq_comp_left", "linear_isometry_equiv.norm_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_within_univ {n : ℕ} : iterated_fderiv_within 𝕜 n f univ = iterated_fderiv 𝕜 n f
begin induction n with n IH, { ext x, simp }, { ext x m, rw [iterated_fderiv_succ_apply_left, iterated_fderiv_within_succ_apply_left, IH, fderiv_within_univ] } end
lemma
iterated_fderiv_within_univ
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "fderiv_within_univ", "iterated_fderiv", "iterated_fderiv_succ_apply_left", "iterated_fderiv_within", "iterated_fderiv_within_succ_apply_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_within_of_is_open (n : ℕ) (hs : is_open s) : eq_on (iterated_fderiv_within 𝕜 n f s) (iterated_fderiv 𝕜 n f) s
begin induction n with n IH, { assume x hx, ext1 m, simp only [iterated_fderiv_within_zero_apply, iterated_fderiv_zero_apply] }, { assume x hx, rw [iterated_fderiv_succ_eq_comp_left, iterated_fderiv_within_succ_eq_comp_left], dsimp, congr' 1, rw fderiv_within_of_open hs hx, apply filte...
lemma
iterated_fderiv_within_of_is_open
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "fderiv_within_of_open", "filter.eventually_eq.fderiv_eq", "is_open", "iterated_fderiv", "iterated_fderiv_succ_eq_comp_left", "iterated_fderiv_within", "iterated_fderiv_within_succ_eq_comp_left", "iterated_fderiv_within_zero_apply", "iterated_fderiv_zero_apply" ]
In an open set, the iterated derivative within this set coincides with the global iterated derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ftaylor_series_within_univ : ftaylor_series_within 𝕜 f univ = ftaylor_series 𝕜 f
begin ext1 x, ext1 n, change iterated_fderiv_within 𝕜 n f univ x = iterated_fderiv 𝕜 n f x, rw iterated_fderiv_within_univ end
lemma
ftaylor_series_within_univ
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "ftaylor_series", "ftaylor_series_within", "iterated_fderiv", "iterated_fderiv_within", "iterated_fderiv_within_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_succ_apply_right {n : ℕ} (m : fin (n + 1) → E) : (iterated_fderiv 𝕜 (n + 1) f x : (fin (n + 1) → E) → F) m = iterated_fderiv 𝕜 n (λy, fderiv 𝕜 f y) x (init m) (m (last n))
begin rw [← iterated_fderiv_within_univ, ← iterated_fderiv_within_univ, ← fderiv_within_univ], exact iterated_fderiv_within_succ_apply_right unique_diff_on_univ (mem_univ _) _ end
theorem
iterated_fderiv_succ_apply_right
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "fderiv", "fderiv_within_univ", "iterated_fderiv", "iterated_fderiv_within_succ_apply_right", "iterated_fderiv_within_univ", "unique_diff_on_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_succ_eq_comp_right {n : ℕ} : iterated_fderiv 𝕜 (n + 1) f x = ((continuous_multilinear_curry_right_equiv' 𝕜 n E F) ∘ (iterated_fderiv 𝕜 n (λy, fderiv 𝕜 f y))) x
by { ext m, rw iterated_fderiv_succ_apply_right, refl }
lemma
iterated_fderiv_succ_eq_comp_right
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "continuous_multilinear_curry_right_equiv'", "fderiv", "iterated_fderiv", "iterated_fderiv_succ_apply_right" ]
Writing explicitly the `n+1`-th derivative as the composition of a currying linear equiv, and the `n`-th derivative of the derivative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_iterated_fderiv_fderiv {n : ℕ} : ‖iterated_fderiv 𝕜 n (fderiv 𝕜 f) x‖ = ‖iterated_fderiv 𝕜 (n + 1) f x‖
by rw [iterated_fderiv_succ_eq_comp_right, linear_isometry_equiv.norm_map]
lemma
norm_iterated_fderiv_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "fderiv", "iterated_fderiv_succ_eq_comp_right", "linear_isometry_equiv.norm_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterated_fderiv_one_apply (m : (fin 1) → E) : (iterated_fderiv 𝕜 1 f x : ((fin 1) → E) → F) m = (fderiv 𝕜 f x : E → F) (m 0)
by { rw [iterated_fderiv_succ_apply_right, iterated_fderiv_zero_apply], refl }
lemma
iterated_fderiv_one_apply
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "fderiv", "iterated_fderiv", "iterated_fderiv_succ_apply_right", "iterated_fderiv_zero_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_iff_ftaylor_series : cont_diff 𝕜 n f ↔ has_ftaylor_series_up_to n f (ftaylor_series 𝕜 f)
begin split, { rw [← cont_diff_on_univ, ← has_ftaylor_series_up_to_on_univ_iff, ← ftaylor_series_within_univ], exact λ h, cont_diff_on.ftaylor_series_within h unique_diff_on_univ }, { assume h, exact ⟨ftaylor_series 𝕜 f, h⟩ } end
theorem
cont_diff_iff_ftaylor_series
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on.ftaylor_series_within", "cont_diff_on_univ", "ftaylor_series", "ftaylor_series_within_univ", "has_ftaylor_series_up_to", "has_ftaylor_series_up_to_on_univ_iff", "unique_diff_on_univ" ]
When a function is `C^n` in a set `s` of unique differentiability, it admits `ftaylor_series_within 𝕜 f s` as a Taylor series up to order `n` in `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_iff_continuous_differentiable : cont_diff 𝕜 n f ↔ (∀ (m : ℕ), (m : ℕ∞) ≤ n → continuous (λ x, iterated_fderiv 𝕜 m f x)) ∧ (∀ (m : ℕ), (m : ℕ∞) < n → differentiable 𝕜 (λ x, iterated_fderiv 𝕜 m f x))
by simp [cont_diff_on_univ.symm, continuous_iff_continuous_on_univ, differentiable_on_univ.symm, iterated_fderiv_within_univ, cont_diff_on_iff_continuous_on_differentiable_on unique_diff_on_univ]
lemma
cont_diff_iff_continuous_differentiable
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on_iff_continuous_on_differentiable_on", "continuous", "continuous_iff_continuous_on_univ", "differentiable", "iterated_fderiv", "iterated_fderiv_within_univ", "unique_diff_on_univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.continuous_iterated_fderiv {m : ℕ} (hm : (m : ℕ∞) ≤ n) (hf : cont_diff 𝕜 n f) : continuous (λ x, iterated_fderiv 𝕜 m f x)
(cont_diff_iff_continuous_differentiable.mp hf).1 m hm
lemma
cont_diff.continuous_iterated_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "continuous", "iterated_fderiv" ]
If `f` is `C^n` then its `m`-times iterated derivative is continuous for `m ≤ n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.differentiable_iterated_fderiv {m : ℕ} (hm : (m : ℕ∞) < n) (hf : cont_diff 𝕜 n f) : differentiable 𝕜 (λ x, iterated_fderiv 𝕜 m f x)
(cont_diff_iff_continuous_differentiable.mp hf).2 m hm
lemma
cont_diff.differentiable_iterated_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "differentiable", "iterated_fderiv" ]
If `f` is `C^n` then its `m`-times iterated derivative is differentiable for `m < n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_of_differentiable_iterated_fderiv (h : ∀(m : ℕ), (m : ℕ∞) ≤ n → differentiable 𝕜 (iterated_fderiv 𝕜 m f)) : cont_diff 𝕜 n f
cont_diff_iff_continuous_differentiable.2 ⟨λ m hm, (h m hm).continuous, λ m hm, (h m (le_of_lt hm))⟩
lemma
cont_diff_of_differentiable_iterated_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "continuous", "differentiable", "iterated_fderiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_succ_iff_fderiv {n : ℕ} : cont_diff 𝕜 ((n + 1) : ℕ) f ↔ differentiable 𝕜 f ∧ cont_diff 𝕜 n (λ y, fderiv 𝕜 f y)
by simp only [← cont_diff_on_univ, ← differentiable_on_univ, ← fderiv_within_univ, cont_diff_on_succ_iff_fderiv_within unique_diff_on_univ]
theorem
cont_diff_succ_iff_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on_succ_iff_fderiv_within", "cont_diff_on_univ", "differentiable", "differentiable_on_univ", "fderiv", "fderiv_within_univ", "unique_diff_on_univ" ]
A function is `C^(n + 1)` if and only if it is differentiable, and its derivative (formulated in terms of `fderiv`) is `C^n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_one_iff_fderiv : cont_diff 𝕜 1 f ↔ differentiable 𝕜 f ∧ continuous (fderiv 𝕜 f)
cont_diff_succ_iff_fderiv.trans $ iff.rfl.and cont_diff_zero
theorem
cont_diff_one_iff_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_zero", "continuous", "differentiable", "fderiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff_top_iff_fderiv : cont_diff 𝕜 ∞ f ↔ differentiable 𝕜 f ∧ cont_diff 𝕜 ∞ (λ y, fderiv 𝕜 f y)
begin simp only [← cont_diff_on_univ, ← differentiable_on_univ, ← fderiv_within_univ], rw cont_diff_on_top_iff_fderiv_within unique_diff_on_univ, end
theorem
cont_diff_top_iff_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_on_top_iff_fderiv_within", "cont_diff_on_univ", "differentiable", "differentiable_on_univ", "fderiv", "fderiv_within_univ", "unique_diff_on_univ" ]
A function is `C^∞` if and only if it is differentiable, and its derivative (formulated in terms of `fderiv`) is `C^∞`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.continuous_fderiv (h : cont_diff 𝕜 n f) (hn : 1 ≤ n) : continuous (λ x, fderiv 𝕜 f x)
((cont_diff_succ_iff_fderiv).1 (h.of_le hn)).2.continuous
lemma
cont_diff.continuous_fderiv
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "cont_diff_succ_iff_fderiv", "continuous", "fderiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cont_diff.continuous_fderiv_apply (h : cont_diff 𝕜 n f) (hn : 1 ≤ n) : continuous (λp : E × E, (fderiv 𝕜 f p.1 : E → F) p.2)
have A : continuous (λq : (E →L[𝕜] F) × E, q.1 q.2) := is_bounded_bilinear_map_apply.continuous, have B : continuous (λp : E × E, (fderiv 𝕜 f p.1, p.2)) := ((h.continuous_fderiv hn).comp continuous_fst).prod_mk continuous_snd, A.comp B
lemma
cont_diff.continuous_fderiv_apply
analysis.calculus
src/analysis/calculus/cont_diff_def.lean
[ "analysis.calculus.fderiv.add", "analysis.calculus.fderiv.mul", "analysis.calculus.fderiv.equiv", "analysis.calculus.fderiv.restrict_scalars", "analysis.calculus.formal_multilinear_series" ]
[ "cont_diff", "continuous", "continuous_fst", "continuous_snd", "fderiv" ]
If a function is at least `C^1`, its bundled derivative (mapping `(x, v)` to `Df(x) v`) is continuous.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_has_deriv_within_at_eq_of_gt_of_lt (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' '' Ioo a b
begin rcases hab.eq_or_lt with rfl | hab', { exact (lt_asymm hma hmb).elim }, set g : ℝ → ℝ := λ x, f x - m * x, have hg : ∀ x ∈ Icc a b, has_deriv_within_at g (f' x - m) (Icc a b) x, { intros x hx, simpa using (hf x hx).sub ((has_deriv_within_at_id x _).const_mul m) }, obtain ⟨c, cmem, hc⟩ : ∃ c ∈ Icc ...
theorem
exists_has_deriv_within_at_eq_of_gt_of_lt
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "continuous_linear_map.map_sub", "continuous_within_at", "has_deriv_at", "has_deriv_within_at", "has_deriv_within_at_id", "interior_Icc", "is_min_on", "mem_interior_iff_mem_nhds", "mem_pos_tangent_cone_at_of_segment_subset", "nonneg_of_mul_nonneg_right", "nonpos_of_mul_nonneg_right", "not_le_o...
**Darboux's theorem**: if `a ≤ b` and `f' a < m < f' b`, then `f' c = m` for some `c ∈ (a, b)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_has_deriv_within_at_eq_of_lt_of_gt (hab : a ≤ b) (hf : ∀ x ∈ (Icc a b), has_deriv_within_at f (f' x) (Icc a b) x) {m : ℝ} (hma : m < f' a) (hmb : f' b < m) : m ∈ f' '' Ioo a b
let ⟨c, cmem, hc⟩ := exists_has_deriv_within_at_eq_of_gt_of_lt hab (λ x hx, (hf x hx).neg) (neg_lt_neg hma) (neg_lt_neg hmb) in ⟨c, cmem, neg_injective hc⟩
theorem
exists_has_deriv_within_at_eq_of_lt_of_gt
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "exists_has_deriv_within_at_eq_of_gt_of_lt", "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
set.ord_connected.image_has_deriv_within_at {s : set ℝ} (hs : ord_connected s) (hf : ∀ x ∈ s, has_deriv_within_at f (f' x) s x) : ord_connected (f' '' s)
begin apply ord_connected_of_Ioo, rintros _ ⟨a, ha, rfl⟩ _ ⟨b, hb, rfl⟩ - m ⟨hma, hmb⟩, cases le_total a b with hab hab, { have : Icc a b ⊆ s, from hs.out ha hb, rcases exists_has_deriv_within_at_eq_of_gt_of_lt hab (λ x hx, (hf x $ this hx).mono this) hma hmb with ⟨c, cmem, hc⟩, exact ⟨c, th...
theorem
set.ord_connected.image_has_deriv_within_at
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "exists_has_deriv_within_at_eq_of_gt_of_lt", "exists_has_deriv_within_at_eq_of_lt_of_gt", "has_deriv_within_at" ]
**Darboux's theorem**: the image of an `ord_connected` set under `f'` is an `ord_connected` set, `has_deriv_within_at` version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set.ord_connected.image_deriv_within {s : set ℝ} (hs : ord_connected s) (hf : differentiable_on ℝ f s) : ord_connected (deriv_within f s '' s)
hs.image_has_deriv_within_at $ λ x hx, (hf x hx).has_deriv_within_at
theorem
set.ord_connected.image_deriv_within
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "deriv_within", "differentiable_on", "has_deriv_within_at" ]
**Darboux's theorem**: the image of an `ord_connected` set under `f'` is an `ord_connected` set, `deriv_within` version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set.ord_connected.image_deriv {s : set ℝ} (hs : ord_connected s) (hf : ∀ x ∈ s, differentiable_at ℝ f x) : ord_connected (deriv f '' s)
hs.image_has_deriv_within_at $ λ x hx, (hf x hx).has_deriv_at.has_deriv_within_at
theorem
set.ord_connected.image_deriv
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "deriv", "differentiable_at", "has_deriv_at.has_deriv_within_at" ]
**Darboux's theorem**: the image of an `ord_connected` set under `f'` is an `ord_connected` set, `deriv` version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex.image_has_deriv_within_at {s : set ℝ} (hs : convex ℝ s) (hf : ∀ x ∈ s, has_deriv_within_at f (f' x) s x) : convex ℝ (f' '' s)
(hs.ord_connected.image_has_deriv_within_at hf).convex
theorem
convex.image_has_deriv_within_at
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "convex", "has_deriv_within_at" ]
**Darboux's theorem**: the image of a convex set under `f'` is a convex set, `has_deriv_within_at` version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex.image_deriv_within {s : set ℝ} (hs : convex ℝ s) (hf : differentiable_on ℝ f s) : convex ℝ (deriv_within f s '' s)
(hs.ord_connected.image_deriv_within hf).convex
theorem
convex.image_deriv_within
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "convex", "deriv_within", "differentiable_on" ]
**Darboux's theorem**: the image of a convex set under `f'` is a convex set, `deriv_within` version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex.image_deriv {s : set ℝ} (hs : convex ℝ s) (hf : ∀ x ∈ s, differentiable_at ℝ f x) : convex ℝ (deriv f '' s)
(hs.ord_connected.image_deriv hf).convex
theorem
convex.image_deriv
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "convex", "deriv", "differentiable_at" ]
**Darboux's theorem**: the image of a convex set under `f'` is a convex set, `deriv` version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_has_deriv_within_at_eq_of_ge_of_le (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_ge_of_le
analysis.calculus
src/analysis/calculus/darboux.lean
[ "analysis.calculus.local_extr" ]
[ "has_deriv_within_at" ]
**Darboux's theorem**: if `a ≤ b` and `f' a ≤ m ≤ f' b`, then `f' c = m` for some `c ∈ [a, b]`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83