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thickening_ball (hε : 0 < ε) (hδ : 0 < δ) (x : E) : thickening ε (ball x δ) = ball x (ε + δ)
by rw [←thickening_singleton, thickening_thickening hε hδ, thickening_singleton]; apply_instance
lemma
thickening_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "thickening_thickening" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
thickening_closed_ball (hε : 0 < ε) (hδ : 0 ≤ δ) (x : E) : thickening ε (closed_ball x δ) = ball x (ε + δ)
by rw [←cthickening_singleton _ hδ, thickening_cthickening hε hδ, thickening_singleton]; apply_instance
lemma
thickening_closed_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "thickening_cthickening" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cthickening_ball (hε : 0 ≤ ε) (hδ : 0 < δ) (x : E) : cthickening ε (ball x δ) = closed_ball x (ε + δ)
by rw [←thickening_singleton, cthickening_thickening hε hδ, cthickening_singleton _ (add_nonneg hε hδ.le)]; apply_instance
lemma
cthickening_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "cthickening_thickening" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cthickening_closed_ball (hε : 0 ≤ ε) (hδ : 0 ≤ δ) (x : E) : cthickening ε (closed_ball x δ) = closed_ball x (ε + δ)
by rw [←cthickening_singleton _ hδ, cthickening_cthickening hε hδ, cthickening_singleton _ (add_nonneg hε hδ)]; apply_instance
lemma
cthickening_closed_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "cthickening_cthickening" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_add_ball (hε : 0 < ε) (hδ : 0 < δ) (a b : E) : ball a ε + ball b δ = ball (a + b) (ε + δ)
by rw [ball_add, thickening_ball hε hδ b, metric.vadd_ball, vadd_eq_add]
lemma
ball_add_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "thickening_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_sub_ball (hε : 0 < ε) (hδ : 0 < δ) (a b : E) : ball a ε - ball b δ = ball (a - b) (ε + δ)
by simp_rw [sub_eq_add_neg, neg_ball, ball_add_ball hε hδ]
lemma
ball_sub_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "ball_add_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_add_closed_ball (hε : 0 < ε) (hδ : 0 ≤ δ) (a b : E) : ball a ε + closed_ball b δ = ball (a + b) (ε + δ)
by rw [ball_add, thickening_closed_ball hε hδ b, metric.vadd_ball, vadd_eq_add]
lemma
ball_add_closed_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "thickening_closed_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_sub_closed_ball (hε : 0 < ε) (hδ : 0 ≤ δ) (a b : E) : ball a ε - closed_ball b δ = ball (a - b) (ε + δ)
by simp_rw [sub_eq_add_neg, neg_closed_ball, ball_add_closed_ball hε hδ]
lemma
ball_sub_closed_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "ball_add_closed_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_ball_add_ball (hε : 0 ≤ ε) (hδ : 0 < δ) (a b : E) : closed_ball a ε + ball b δ = ball (a + b) (ε + δ)
by rw [add_comm, ball_add_closed_ball hδ hε b, add_comm, add_comm δ]
lemma
closed_ball_add_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "ball_add_closed_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_ball_sub_ball (hε : 0 ≤ ε) (hδ : 0 < δ) (a b : E) : closed_ball a ε - ball b δ = ball (a - b) (ε + δ)
by simp_rw [sub_eq_add_neg, neg_ball, closed_ball_add_ball hε hδ]
lemma
closed_ball_sub_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "closed_ball_add_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_ball_add_closed_ball [proper_space E] (hε : 0 ≤ ε) (hδ : 0 ≤ δ) (a b : E) : closed_ball a ε + closed_ball b δ = closed_ball (a + b) (ε + δ)
by rw [(is_compact_closed_ball _ _).add_closed_ball hδ b, cthickening_closed_ball hδ hε a, metric.vadd_closed_ball, vadd_eq_add, add_comm, add_comm δ]
lemma
closed_ball_add_closed_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "cthickening_closed_ball", "proper_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_ball_sub_closed_ball [proper_space E] (hε : 0 ≤ ε) (hδ : 0 ≤ δ) (a b : E) : closed_ball a ε - closed_ball b δ = closed_ball (a - b) (ε + δ)
by simp_rw [sub_eq_add_neg, neg_closed_ball, closed_ball_add_closed_ball hε hδ]
lemma
closed_ball_sub_closed_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "closed_ball_add_closed_ball", "proper_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_closed_ball (c : 𝕜) (x : E) {r : ℝ} (hr : 0 ≤ r) : c • closed_ball x r = closed_ball (c • x) (‖c‖ * r)
begin rcases eq_or_ne c 0 with rfl|hc, { simp [hr, zero_smul_set, set.singleton_zero, ← nonempty_closed_ball] }, { exact smul_closed_ball' hc x r } end
theorem
smul_closed_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "eq_or_ne", "smul_closed_ball'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_closed_unit_ball (c : 𝕜) : c • closed_ball (0 : E) (1 : ℝ) = closed_ball (0 : E) (‖c‖)
by rw [smul_closed_ball _ _ zero_le_one, smul_zero, mul_one]
lemma
smul_closed_unit_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "mul_one", "smul_closed_ball", "smul_zero", "zero_le_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_closed_unit_ball_of_nonneg {r : ℝ} (hr : 0 ≤ r) : r • closed_ball 0 1 = closed_ball (0 : E) r
by rw [smul_closed_unit_ball, real.norm_of_nonneg hr]
lemma
smul_closed_unit_ball_of_nonneg
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "real.norm_of_nonneg", "smul_closed_unit_ball" ]
In a real normed space, the image of the unit closed ball under multiplication by a nonnegative number `r` is the closed ball of radius `r` with center at the origin.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normed_space.sphere_nonempty [nontrivial E] {x : E} {r : ℝ} : (sphere x r).nonempty ↔ 0 ≤ r
begin obtain ⟨y, hy⟩ := exists_ne x, refine ⟨λ h, nonempty_closed_ball.1 (h.mono sphere_subset_closed_ball), λ hr, ⟨r • ‖y - x‖⁻¹ • (y - x) + x, _⟩⟩, have : ‖y - x‖ ≠ 0, by simpa [sub_eq_zero], simp [norm_smul, this, real.norm_of_nonneg hr], end
lemma
normed_space.sphere_nonempty
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "exists_ne", "nontrivial", "norm_smul", "real.norm_of_nonneg" ]
In a nontrivial real normed space, a sphere is nonempty if and only if its radius is nonnegative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_sphere [nontrivial E] (c : 𝕜) (x : E) {r : ℝ} (hr : 0 ≤ r) : c • sphere x r = sphere (c • x) (‖c‖ * r)
begin rcases eq_or_ne c 0 with rfl|hc, { simp [zero_smul_set, set.singleton_zero, hr] }, { exact smul_sphere' hc x r } end
lemma
smul_sphere
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "eq_or_ne", "nontrivial", "smul_sphere'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
affinity_unit_ball {r : ℝ} (hr : 0 < r) (x : E) : x +ᵥ r • ball 0 1 = ball x r
by rw [smul_unit_ball_of_pos hr, vadd_ball_zero]
lemma
affinity_unit_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "smul_unit_ball_of_pos" ]
Any ball `metric.ball x r`, `0 < r` is the image of the unit ball under `λ y, x + r • y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
affinity_unit_closed_ball {r : ℝ} (hr : 0 ≤ r) (x : E) : x +ᵥ r • closed_ball 0 1 = closed_ball x r
by rw [smul_closed_unit_ball, real.norm_of_nonneg hr, vadd_closed_ball_zero]
lemma
affinity_unit_closed_ball
analysis.normed_space
src/analysis/normed_space/pointwise.lean
[ "analysis.normed.group.add_torsor", "analysis.normed.group.pointwise", "analysis.normed_space.basic" ]
[ "real.norm_of_nonneg", "smul_closed_unit_ball", "vadd_closed_ball_zero" ]
Any closed ball `metric.closed_ball x r`, `0 ≤ r` is the image of the unit closed ball under `λ y, x + r • y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exp_coe (r : ℝ) : exp ℝ (r : ℍ[ℝ]) = ↑(exp ℝ r)
(map_exp ℝ (algebra_map ℝ ℍ[ℝ]) (continuous_algebra_map _ _) _).symm
lemma
quaternion.exp_coe
analysis.normed_space
src/analysis/normed_space/quaternion_exponential.lean
[ "analysis.quaternion", "analysis.normed_space.exponential", "analysis.special_functions.trigonometric.series" ]
[ "algebra_map", "continuous_algebra_map", "exp", "map_exp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_sum_exp_series_of_imaginary {q : quaternion ℝ} (hq : q.re = 0) {c s : ℝ} (hc : has_sum (λ n, (-1)^n * ‖q‖^(2 * n) / (2 * n)!) c) (hs : has_sum (λ n, (-1)^n * ‖q‖^(2 * n + 1) / (2 * n + 1)!) s) : has_sum (λ n, exp_series ℝ _ n (λ _, q)) (↑c + (s / ‖q‖) • q)
begin replace hc := has_sum_coe.mpr hc, replace hs := (hs.div_const ‖q‖).smul_const q, obtain rfl | hq0 := eq_or_ne q 0, { simp_rw [exp_series_apply_zero, norm_zero, div_zero, zero_smul, add_zero], simp_rw [norm_zero] at hc, convert hc, ext (_ | n) : 1, { rw [pow_zero, mul_zero, pow_zero, nat.fa...
lemma
quaternion.has_sum_exp_series_of_imaginary
analysis.normed_space
src/analysis/normed_space/quaternion_exponential.lean
[ "analysis.quaternion", "analysis.normed_space.exponential", "analysis.special_functions.trigonometric.series" ]
[ "div_div_cancel_left'", "div_eq_mul_inv", "div_one", "div_zero", "eq_or_ne", "exp_series", "exp_series_apply_eq", "exp_series_apply_zero", "has_sum", "has_sum.even_add_odd", "mul_div_assoc", "mul_zero", "nat.cast_one", "nat.factorial_zero", "neg_pow", "one_mul", "pow_mul", "pow_suc...
Auxiliary result; if the power series corresponding to `real.cos` and `real.sin` evaluated at `‖q‖` tend to `c` and `s`, then the exponential series tends to `c + (s / ‖q‖)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exp_of_re_eq_zero (q : quaternion ℝ) (hq : q.re = 0) : exp ℝ q = ↑(real.cos ‖q‖) + (real.sin ‖q‖ / ‖q‖) • q
begin rw [exp_eq_tsum], refine has_sum.tsum_eq _, simp_rw ← exp_series_apply_eq, exact has_sum_exp_series_of_imaginary hq (real.has_sum_cos _) (real.has_sum_sin _), end
lemma
quaternion.exp_of_re_eq_zero
analysis.normed_space
src/analysis/normed_space/quaternion_exponential.lean
[ "analysis.quaternion", "analysis.normed_space.exponential", "analysis.special_functions.trigonometric.series" ]
[ "exp", "exp_eq_tsum", "exp_series_apply_eq", "has_sum.tsum_eq", "quaternion", "real.cos", "real.has_sum_cos", "real.has_sum_sin", "real.sin" ]
The closed form for the quaternion exponential on imaginary quaternions.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exp_eq (q : quaternion ℝ) : exp ℝ q = exp ℝ q.re • (↑(real.cos ‖q.im‖) + (real.sin ‖q.im‖ / ‖q.im‖) • q.im)
begin rw [←exp_of_re_eq_zero q.im q.im_re, ←coe_mul_eq_smul, ←exp_coe, ←exp_add_of_commute, re_add_im], exact algebra.commutes q.re (_ : ℍ[ℝ]), end
lemma
quaternion.exp_eq
analysis.normed_space
src/analysis/normed_space/quaternion_exponential.lean
[ "analysis.quaternion", "analysis.normed_space.exponential", "analysis.special_functions.trigonometric.series" ]
[ "algebra.commutes", "exp", "quaternion", "real.cos", "real.sin" ]
The closed form for the quaternion exponential on arbitrary quaternions.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
re_exp (q : ℍ[ℝ]) : (exp ℝ q).re = exp ℝ q.re * (real.cos ‖q - q.re‖)
by simp [exp_eq]
lemma
quaternion.re_exp
analysis.normed_space
src/analysis/normed_space/quaternion_exponential.lean
[ "analysis.quaternion", "analysis.normed_space.exponential", "analysis.special_functions.trigonometric.series" ]
[ "exp", "real.cos" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
im_exp (q : ℍ[ℝ]) : (exp ℝ q).im = (exp ℝ q.re * (real.sin ‖q.im‖ / ‖q.im‖)) • q.im
by simp [exp_eq, smul_smul]
lemma
quaternion.im_exp
analysis.normed_space
src/analysis/normed_space/quaternion_exponential.lean
[ "analysis.quaternion", "analysis.normed_space.exponential", "analysis.special_functions.trigonometric.series" ]
[ "exp", "real.sin", "smul_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_sq_exp (q : ℍ[ℝ]) : norm_sq (exp ℝ q) = (exp ℝ q.re)^2
calc norm_sq (exp ℝ q) = norm_sq (exp ℝ q.re • (↑(real.cos ‖q.im‖) + (real.sin ‖q.im‖ / ‖q.im‖) • q.im)) : by rw exp_eq ... = (exp ℝ q.re)^2 * norm_sq ((↑(real.cos ‖q.im‖) + (real.sin ‖q.im‖ / ‖q.im‖) • q.im)) : by rw [norm_sq_smul] ... = (exp ℝ q.re)^2 * ((real.cos ‖q.im‖) ^ 2 + (real.sin ‖q.im‖)^2) : ...
lemma
quaternion.norm_sq_exp
analysis.normed_space
src/analysis/normed_space/quaternion_exponential.lean
[ "analysis.quaternion", "analysis.normed_space.exponential", "analysis.special_functions.trigonometric.series" ]
[ "div_mul_cancel", "div_pow", "eq_or_ne", "exp", "mul_one", "mul_zero", "pow_ne_zero", "real.cos", "real.cos_sq_add_sin_sq", "real.sin", "smul_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_exp (q : ℍ[ℝ]) : ‖exp ℝ q‖ = ‖exp ℝ q.re‖
by rw [norm_eq_sqrt_real_inner (exp ℝ q), inner_self, norm_sq_exp, real.sqrt_sq_eq_abs, real.norm_eq_abs]
lemma
quaternion.norm_exp
analysis.normed_space
src/analysis/normed_space/quaternion_exponential.lean
[ "analysis.quaternion", "analysis.normed_space.exponential", "analysis.special_functions.trigonometric.series" ]
[ "exp", "norm_eq_sqrt_real_inner", "real.norm_eq_abs", "real.sqrt_sq_eq_abs" ]
Note that this implies that exponentials of pure imaginary quaternions are unit quaternions since in that case the RHS is `1` via `exp_zero` and `norm_one`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_add (h : same_ray ℝ x y) : ‖x + y‖ = ‖x‖ + ‖y‖
begin rcases h.exists_eq_smul with ⟨u, a, b, ha, hb, -, rfl, rfl⟩, rw [← add_smul, norm_smul_of_nonneg (add_nonneg ha hb), norm_smul_of_nonneg ha, norm_smul_of_nonneg hb, add_mul] end
lemma
same_ray.norm_add
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "add_smul", "norm_smul_of_nonneg", "same_ray" ]
If `x` and `y` are on the same ray, then the triangle inequality becomes the equality: the norm of `x + y` is the sum of the norms of `x` and `y`. The converse is true for a strictly convex space.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_sub (h : same_ray ℝ x y) : ‖x - y‖ = |‖x‖ - ‖y‖|
begin rcases h.exists_eq_smul with ⟨u, a, b, ha, hb, -, rfl, rfl⟩, wlog hab : b ≤ a, { rw same_ray_comm at h, rw [norm_sub_rev, abs_sub_comm], exact this u b a hb ha h (le_of_not_le hab), }, rw ← sub_nonneg at hab, rw [← sub_smul, norm_smul_of_nonneg hab, norm_smul_of_nonneg ha, norm_smul_of_nonneg hb...
lemma
same_ray.norm_sub
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "abs_of_nonneg", "abs_sub_comm", "norm_smul_of_nonneg", "same_ray", "same_ray_comm", "sub_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_smul_eq (h : same_ray ℝ x y) : ‖x‖ • y = ‖y‖ • x
begin rcases h.exists_eq_smul with ⟨u, a, b, ha, hb, -, rfl, rfl⟩, simp only [norm_smul_of_nonneg, *, mul_smul, smul_comm (‖u‖)], apply smul_comm end
lemma
same_ray.norm_smul_eq
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "norm_smul_of_nonneg", "same_ray" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_inj_on_ray_left (hx : x ≠ 0) : {y | same_ray ℝ x y}.inj_on norm
begin rintro y hy z hz h, rcases hy.exists_nonneg_left hx with ⟨r, hr, rfl⟩, rcases hz.exists_nonneg_left hx with ⟨s, hs, rfl⟩, rw [norm_smul, norm_smul, mul_left_inj' (norm_ne_zero_iff.2 hx), norm_of_nonneg hr, norm_of_nonneg hs] at h, rw h end
lemma
norm_inj_on_ray_left
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "mul_left_inj'", "norm_smul", "same_ray" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_inj_on_ray_right (hy : y ≠ 0) : {x | same_ray ℝ x y}.inj_on norm
by simpa only [same_ray_comm] using norm_inj_on_ray_left hy
lemma
norm_inj_on_ray_right
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "norm_inj_on_ray_left", "same_ray", "same_ray_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
same_ray_iff_norm_smul_eq : same_ray ℝ x y ↔ ‖x‖ • y = ‖y‖ • x
⟨same_ray.norm_smul_eq, λ h, or_iff_not_imp_left.2 $ λ hx, or_iff_not_imp_left.2 $ λ hy, ⟨‖y‖, ‖x‖, norm_pos_iff.2 hy, norm_pos_iff.2 hx, h.symm⟩⟩
lemma
same_ray_iff_norm_smul_eq
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "same_ray" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
same_ray_iff_inv_norm_smul_eq_of_ne (hx : x ≠ 0) (hy : y ≠ 0) : same_ray ℝ x y ↔ ‖x‖⁻¹ • x = ‖y‖⁻¹ • y
by rw [inv_smul_eq_iff₀, smul_comm, eq_comm, inv_smul_eq_iff₀, same_ray_iff_norm_smul_eq]; rwa norm_ne_zero_iff
lemma
same_ray_iff_inv_norm_smul_eq_of_ne
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "inv_smul_eq_iff₀", "same_ray", "same_ray_iff_norm_smul_eq" ]
Two nonzero vectors `x y` in a real normed space are on the same ray if and only if the unit vectors `‖x‖⁻¹ • x` and `‖y‖⁻¹ • y` are equal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
same_ray_iff_inv_norm_smul_eq : same_ray ℝ x y ↔ x = 0 ∨ y = 0 ∨ ‖x‖⁻¹ • x = ‖y‖⁻¹ • y
begin rcases eq_or_ne x 0 with rfl|hx, { simp [same_ray.zero_left] }, rcases eq_or_ne y 0 with rfl|hy, { simp [same_ray.zero_right] }, simp only [same_ray_iff_inv_norm_smul_eq_of_ne hx hy, *, false_or] end
lemma
same_ray_iff_inv_norm_smul_eq
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "eq_or_ne", "same_ray", "same_ray.zero_left", "same_ray.zero_right", "same_ray_iff_inv_norm_smul_eq_of_ne" ]
Two vectors `x y` in a real normed space are on the ray if and only if one of them is zero or the unit vectors `‖x‖⁻¹ • x` and `‖y‖⁻¹ • y` are equal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
same_ray_iff_of_norm_eq (h : ‖x‖ = ‖y‖) : same_ray ℝ x y ↔ x = y
begin obtain rfl | hy := eq_or_ne y 0, { rw [norm_zero, norm_eq_zero] at h, exact iff_of_true (same_ray.zero_right _) h }, { exact ⟨λ hxy, norm_inj_on_ray_right hy hxy same_ray.rfl h, λ hxy, hxy ▸ same_ray.rfl⟩ } end
lemma
same_ray_iff_of_norm_eq
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "eq_or_ne", "iff_of_true", "norm_eq_zero", "norm_inj_on_ray_right", "same_ray", "same_ray.rfl", "same_ray.zero_right" ]
Two vectors of the same norm are on the same ray if and only if they are equal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
not_same_ray_iff_of_norm_eq (h : ‖x‖ = ‖y‖) : ¬ same_ray ℝ x y ↔ x ≠ y
(same_ray_iff_of_norm_eq h).not
lemma
not_same_ray_iff_of_norm_eq
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "same_ray", "same_ray_iff_of_norm_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
same_ray.eq_of_norm_eq (h : same_ray ℝ x y) (hn : ‖x‖ = ‖y‖) : x = y
(same_ray_iff_of_norm_eq hn).mp h
lemma
same_ray.eq_of_norm_eq
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "same_ray", "same_ray_iff_of_norm_eq" ]
If two points on the same ray have the same norm, then they are equal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
same_ray.norm_eq_iff (h : same_ray ℝ x y) : ‖x‖ = ‖y‖ ↔ x = y
⟨h.eq_of_norm_eq, λ h, h ▸ rfl⟩
lemma
same_ray.norm_eq_iff
analysis.normed_space
src/analysis/normed_space/ray.lean
[ "linear_algebra.ray", "analysis.normed_space.basic" ]
[ "same_ray" ]
The norms of two vectors on the same ray are equal if and only if they are equal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
riesz_lemma {F : subspace 𝕜 E} (hFc : is_closed (F : set E)) (hF : ∃ x : E, x ∉ F) {r : ℝ} (hr : r < 1) : ∃ x₀ : E, x₀ ∉ F ∧ ∀ y ∈ F, r * ‖x₀‖ ≤ ‖x₀ - y‖
begin classical, obtain ⟨x, hx⟩ : ∃ x : E, x ∉ F := hF, let d := metric.inf_dist x F, have hFn : (F : set E).nonempty, from ⟨_, F.zero_mem⟩, have hdp : 0 < d, from lt_of_le_of_ne metric.inf_dist_nonneg (λ heq, hx ((hFc.mem_iff_inf_dist_zero hFn).2 heq.symm)), let r' := max r 2⁻¹, have hr' : r' < 1...
lemma
riesz_lemma
analysis.normed_space
src/analysis/normed_space/riesz_lemma.lean
[ "analysis.normed_space.basic", "topology.metric_space.hausdorff_distance" ]
[ "by_contradiction", "is_closed", "lt_div_iff", "lt_div_iff'", "metric.inf_dist", "metric.inf_dist_le_dist_of_mem", "metric.inf_dist_lt_iff", "metric.inf_dist_nonneg", "mul_le_mul_of_nonneg_right", "mul_lt_iff_lt_one_right", "subspace" ]
Riesz's lemma, which usually states that it is possible to find a vector with norm 1 whose distance to a closed proper subspace is arbitrarily close to 1. The statement here is in terms of multiples of norms, since in general the existence of an element of norm exactly 1 is not guaranteed. For a variant giving an eleme...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
riesz_lemma_of_norm_lt {c : 𝕜} (hc : 1 < ‖c‖) {R : ℝ} (hR : ‖c‖ < R) {F : subspace 𝕜 E} (hFc : is_closed (F : set E)) (hF : ∃ x : E, x ∉ F) : ∃ x₀ : E, ‖x₀‖ ≤ R ∧ ∀ y ∈ F, 1 ≤ ‖x₀ - y‖
begin have Rpos : 0 < R := (norm_nonneg _).trans_lt hR, have : ‖c‖ / R < 1, by { rw div_lt_iff Rpos, simpa using hR }, rcases riesz_lemma hFc hF this with ⟨x, xF, hx⟩, have x0 : x ≠ 0 := λ H, by simpa [H] using xF, obtain ⟨d, d0, dxlt, ledx, -⟩ : ∃ (d : 𝕜), d ≠ 0 ∧ ‖d • x‖ < R ∧ R / ‖c‖ ≤ ‖d • x‖ ∧ ‖d‖⁻¹...
lemma
riesz_lemma_of_norm_lt
analysis.normed_space
src/analysis/normed_space/riesz_lemma.lean
[ "analysis.normed_space.basic", "topology.metric_space.hausdorff_distance" ]
[ "div_lt_iff", "div_nonneg", "is_closed", "mul_inv_cancel", "mul_le_mul_of_nonneg_left", "norm_smul", "rescale_to_shell", "riesz_lemma", "ring", "smul_smul", "smul_sub", "submodule.smul_mem", "subspace" ]
A version of Riesz lemma: given a strict closed subspace `F`, one may find an element of norm `≤ R` which is at distance at least `1` of every element of `F`. Here, `R` is any given constant strictly larger than the norm of an element of norm `> 1`. For a version without an `R`, see `riesz_lemma`. Since we are consid...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
metric.closed_ball_inf_dist_compl_subset_closure {x : F} {s : set F} (hx : x ∈ s) : closed_ball x (inf_dist x sᶜ) ⊆ closure s
begin cases eq_or_ne (inf_dist x sᶜ) 0 with h₀ h₀, { rw [h₀, closed_ball_zero'], exact closure_mono (singleton_subset_iff.2 hx) }, { rw ← closure_ball x h₀, exact closure_mono ball_inf_dist_compl_subset } end
lemma
metric.closed_ball_inf_dist_compl_subset_closure
analysis.normed_space
src/analysis/normed_space/riesz_lemma.lean
[ "analysis.normed_space.basic", "topology.metric_space.hausdorff_distance" ]
[ "closure", "closure_ball", "closure_mono", "eq_or_ne" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
spectral_radius (𝕜 : Type*) {A : Type*} [normed_field 𝕜] [ring A] [algebra 𝕜 A] (a : A) : ℝ≥0∞
⨆ k ∈ spectrum 𝕜 a, ‖k‖₊
def
spectral_radius
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "algebra", "normed_field", "ring", "spectrum" ]
The *spectral radius* is the supremum of the `nnnorm` (`‖⬝‖₊`) of elements in the spectrum, coerced into an element of `ℝ≥0∞`. Note that it is possible for `spectrum 𝕜 a = ∅`. In this case, `spectral_radius a = 0`. It is also possible that `spectrum 𝕜 a` be unbounded (though not for Banach algebras, see ...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
spectral_radius.of_subsingleton [subsingleton A] (a : A) : spectral_radius 𝕜 a = 0
by simp [spectral_radius]
lemma
spectrum.spectral_radius.of_subsingleton
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "spectral_radius" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
spectral_radius_zero : spectral_radius 𝕜 (0 : A) = 0
by { nontriviality A, simp [spectral_radius] }
lemma
spectrum.spectral_radius_zero
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "spectral_radius" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_resolvent_set_of_spectral_radius_lt {a : A} {k : 𝕜} (h : spectral_radius 𝕜 a < ‖k‖₊) : k ∈ ρ a
not_not.mp $ λ hn, h.not_le $ le_supr₂ k hn
lemma
spectrum.mem_resolvent_set_of_spectral_radius_lt
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "le_supr₂", "spectral_radius" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_resolvent_set (a : A) : is_open (ρ a)
units.is_open.preimage ((continuous_algebra_map 𝕜 A).sub continuous_const)
lemma
spectrum.is_open_resolvent_set
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "continuous_algebra_map", "continuous_const", "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed (a : A) : is_closed (σ a)
(is_open_resolvent_set a).is_closed_compl
lemma
spectrum.is_closed
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "is_closed" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_resolvent_set_of_norm_lt_mul {a : A} {k : 𝕜} (h : ‖a‖ * ‖(1 : A)‖ < ‖k‖) : k ∈ ρ a
begin rw [resolvent_set, set.mem_set_of_eq, algebra.algebra_map_eq_smul_one], nontriviality A, have hk : k ≠ 0, from ne_zero_of_norm_ne_zero ((mul_nonneg (norm_nonneg _) (norm_nonneg _)).trans_lt h).ne', let ku := units.map (↑ₐ).to_monoid_hom (units.mk0 k hk), rw [←inv_inv (‖(1 : A)‖), mul_inv_lt_iff (inv...
lemma
spectrum.mem_resolvent_set_of_norm_lt_mul
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "algebra.algebra_map_eq_smul_one", "is_unit", "mul_inv_lt_iff", "norm_algebra_map", "one_ne_zero", "resolvent_set", "units.map", "units.mk0" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_resolvent_set_of_norm_lt [norm_one_class A] {a : A} {k : 𝕜} (h : ‖a‖ < ‖k‖) : k ∈ ρ a
mem_resolvent_set_of_norm_lt_mul (by rwa [norm_one, mul_one])
lemma
spectrum.mem_resolvent_set_of_norm_lt
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "mul_one", "norm_one_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_le_norm_mul_of_mem {a : A} {k : 𝕜} (hk : k ∈ σ a) : ‖k‖ ≤ ‖a‖ * ‖(1 : A)‖
le_of_not_lt $ mt mem_resolvent_set_of_norm_lt_mul hk
lemma
spectrum.norm_le_norm_mul_of_mem
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_le_norm_of_mem [norm_one_class A] {a : A} {k : 𝕜} (hk : k ∈ σ a) : ‖k‖ ≤ ‖a‖
le_of_not_lt $ mt mem_resolvent_set_of_norm_lt hk
lemma
spectrum.norm_le_norm_of_mem
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "norm_one_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subset_closed_ball_norm_mul (a : A) : σ a ⊆ metric.closed_ball (0 : 𝕜) (‖a‖ * ‖(1 : A)‖)
λ k hk, by simp [norm_le_norm_mul_of_mem hk]
lemma
spectrum.subset_closed_ball_norm_mul
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "metric.closed_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subset_closed_ball_norm [norm_one_class A] (a : A) : σ a ⊆ metric.closed_ball (0 : 𝕜) (‖a‖)
λ k hk, by simp [norm_le_norm_of_mem hk]
lemma
spectrum.subset_closed_ball_norm
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "metric.closed_ball", "norm_one_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_bounded (a : A) : metric.bounded (σ a)
(metric.bounded_iff_subset_ball 0).mpr ⟨‖a‖ * ‖(1 : A)‖, subset_closed_ball_norm_mul a⟩
lemma
spectrum.is_bounded
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "metric.bounded", "metric.bounded_iff_subset_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact [proper_space 𝕜] (a : A) : is_compact (σ a)
metric.is_compact_of_is_closed_bounded (spectrum.is_closed a) (is_bounded a)
theorem
spectrum.is_compact
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "is_compact", "metric.is_compact_of_is_closed_bounded", "proper_space", "spectrum.is_closed" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
spectral_radius_le_nnnorm [norm_one_class A] (a : A) : spectral_radius 𝕜 a ≤ ‖a‖₊
by { refine supr₂_le (λ k hk, _), exact_mod_cast norm_le_norm_of_mem hk }
theorem
spectrum.spectral_radius_le_nnnorm
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "norm_one_class", "spectral_radius", "supr₂_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_nnnorm_eq_spectral_radius_of_nonempty [proper_space 𝕜] {a : A} (ha : (σ a).nonempty) : ∃ k ∈ σ a, (‖k‖₊ : ℝ≥0∞) = spectral_radius 𝕜 a
begin obtain ⟨k, hk, h⟩ := (spectrum.is_compact a).exists_forall_ge ha continuous_nnnorm.continuous_on, exact ⟨k, hk, le_antisymm (le_supr₂ k hk) (supr₂_le $ by exact_mod_cast h)⟩, end
lemma
spectrum.exists_nnnorm_eq_spectral_radius_of_nonempty
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "le_supr₂", "proper_space", "spectral_radius", "spectrum.is_compact", "supr₂_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
spectral_radius_lt_of_forall_lt_of_nonempty [proper_space 𝕜] {a : A} (ha : (σ a).nonempty) {r : ℝ≥0} (hr : ∀ k ∈ σ a, ‖k‖₊ < r) : spectral_radius 𝕜 a < r
Sup_image.symm.trans_lt $ ((spectrum.is_compact a).Sup_lt_iff_of_continuous ha (ennreal.continuous_coe.comp continuous_nnnorm).continuous_on (r : ℝ≥0∞)).mpr (by exact_mod_cast hr)
lemma
spectrum.spectral_radius_lt_of_forall_lt_of_nonempty
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "continuous_on", "proper_space", "spectral_radius", "spectrum.is_compact" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
spectral_radius_le_pow_nnnorm_pow_one_div (a : A) (n : ℕ) : spectral_radius 𝕜 a ≤ (‖a ^ (n + 1)‖₊) ^ (1 / (n + 1) : ℝ) * (‖(1 : A)‖₊) ^ (1 / (n + 1) : ℝ)
begin refine supr₂_le (λ k hk, _), /- apply easy direction of the spectral mapping theorem for polynomials -/ have pow_mem : k ^ (n + 1) ∈ σ (a ^ (n + 1)), by simpa only [one_mul, algebra.algebra_map_eq_smul_one, one_smul, aeval_monomial, one_mul, eval_monomial] using subset_polynomial_aeval a (monomial...
theorem
spectrum.spectral_radius_le_pow_nnnorm_pow_one_div
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "algebra.algebra_map_eq_smul_one", "ennreal.coe_mul", "ennreal.coe_mul_rpow", "mul_one_div_cancel", "nat.cast_succ", "nat.succ_pos'", "nnnorm_pow", "nnnorm_pow_le", "one_mul", "one_smul", "pow_mem", "real.to_nnreal_mono", "real.to_nnreal_mul", "spectral_radius", "supr₂_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
spectral_radius_le_liminf_pow_nnnorm_pow_one_div (a : A) : spectral_radius 𝕜 a ≤ at_top.liminf (λ n : ℕ, (‖a ^ n‖₊ : ℝ≥0∞) ^ (1 / n : ℝ))
begin refine ennreal.le_of_forall_lt_one_mul_le (λ ε hε, _), by_cases ε = 0, { simp only [h, zero_mul, zero_le'] }, have hε' : ε⁻¹ ≠ ∞, from λ h', h (by simpa only [inv_inv, inv_top] using congr_arg (λ (x : ℝ≥0∞), x⁻¹) h'), simp only [ennreal.mul_le_iff_le_inv h (hε.trans_le le_top).ne, mul_comm ε⁻¹, ...
theorem
spectrum.spectral_radius_le_liminf_pow_nnnorm_pow_one_div
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "ennreal.coe_ne_top", "ennreal.eventually_pow_one_div_le", "ennreal.infi_mul", "ennreal.le_of_forall_lt_one_mul_le", "ennreal.mul_le_iff_le_inv", "ennreal.supr_mul", "inv_inv", "inv_one", "le_infi", "le_supr", "le_top", "mul_comm", "mul_le_mul_left'", "spectral_radius", "zero_le'", "ze...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_deriv_at_resolvent {a : A} {k : 𝕜} (hk : k ∈ ρ a) : has_deriv_at (resolvent a) (-(resolvent a k) ^ 2) k
begin have H₁ : has_fderiv_at ring.inverse _ (↑ₐk - a) := has_fderiv_at_ring_inverse hk.unit, have H₂ : has_deriv_at (λ k, ↑ₐk - a) 1 k, { simpa using (algebra.linear_map 𝕜 A).has_deriv_at.sub_const a }, simpa [resolvent, sq, hk.unit_spec, ← ring.inverse_unit hk.unit] using H₁.comp_has_deriv_at k H₂, end
theorem
spectrum.has_deriv_at_resolvent
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "algebra.linear_map", "has_deriv_at", "has_deriv_at.sub_const", "has_fderiv_at", "has_fderiv_at_ring_inverse", "resolvent", "ring.inverse", "ring.inverse_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_resolvent_le_forall (a : A) : ∀ ε > 0, ∃ R > 0, ∀ z : 𝕜, R ≤ ‖z‖ → ‖resolvent a z‖ ≤ ε
begin obtain ⟨c, c_pos, hc⟩ := (@normed_ring.inverse_one_sub_norm A _ _).exists_pos, rw [is_O_with_iff, eventually_iff, metric.mem_nhds_iff] at hc, rcases hc with ⟨δ, δ_pos, hδ⟩, simp only [cstar_ring.norm_one, mul_one] at hδ, intros ε hε, have ha₁ : 0 < ‖a‖ + 1 := lt_of_le_of_lt (norm_nonneg a) (lt_add_one...
lemma
spectrum.norm_resolvent_le_forall
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "algebra.algebra_map_eq_smul_one", "cstar_ring.norm_one", "inv_le_of_inv_le", "inv_mul_cancel_right₀", "inv_mul_lt_iff", "is_unit", "lt_add_one", "metric.mem_nhds_iff", "mul_assoc", "mul_le_mul", "mul_le_mul_of_nonneg_right", "mul_lt_mul_of_pos_left", "mul_one", "norm_inv", "norm_smul", ...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_fpower_series_on_ball_inverse_one_sub_smul [complete_space A] (a : A) : has_fpower_series_on_ball (λ z : 𝕜, ring.inverse (1 - z • a)) (λ n, continuous_multilinear_map.mk_pi_field 𝕜 (fin n) (a ^ n)) 0 (‖a‖₊)⁻¹
{ r_le := begin refine le_of_forall_nnreal_lt (λ r hr, le_radius_of_bound_nnreal _ (max 1 ‖(1 : A)‖₊) (λ n, _)), rw [←norm_to_nnreal, norm_mk_pi_field, norm_to_nnreal], cases n, { simp only [le_refl, mul_one, or_true, le_max_iff, pow_zero] }, { refine le_trans (le_trans (mul_le_mul_right' (nnnorm_...
lemma
spectrum.has_fpower_series_on_ball_inverse_one_sub_smul
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "complete_space", "continuous_multilinear_map.mk_pi_field", "has_fpower_series_on_ball", "has_sum", "le_max_iff", "metric.emetric_ball_nnreal", "mul_comm", "mul_le_mul_right'", "mul_one", "nnnorm_pow_le'", "nnnorm_smul", "nnreal.lt_inv_iff_mul_lt", "normed_ring.inverse_one_sub", "normed_ri...
In a Banach algebra `A` over a nontrivially normed field `𝕜`, for any `a : A` the power series with coefficients `a ^ n` represents the function `(1 - z • a)⁻¹` in a disk of radius `‖a‖₊⁻¹`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit_one_sub_smul_of_lt_inv_radius {a : A} {z : 𝕜} (h : ↑‖z‖₊ < (spectral_radius 𝕜 a)⁻¹) : is_unit (1 - z • a)
begin by_cases hz : z = 0, { simp only [hz, is_unit_one, sub_zero, zero_smul] }, { let u := units.mk0 z hz, suffices hu : is_unit (u⁻¹ • 1 - a), { rwa [is_unit.smul_sub_iff_sub_inv_smul, inv_inv u] at hu }, { rw [units.smul_def, ←algebra.algebra_map_eq_smul_one, ←mem_resolvent_set_iff], refine m...
lemma
spectrum.is_unit_one_sub_smul_of_lt_inv_radius
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "inv_inv", "is_unit", "is_unit.smul_sub_iff_sub_inv_smul", "is_unit_one", "nnnorm_inv", "spectral_radius", "units.coe_inv", "units.coe_mk0", "units.mk0", "units.smul_def", "zero_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
differentiable_on_inverse_one_sub_smul [complete_space A] {a : A} {r : ℝ≥0} (hr : (r : ℝ≥0∞) < (spectral_radius 𝕜 a)⁻¹) : differentiable_on 𝕜 (λ z : 𝕜, ring.inverse (1 - z • a)) (metric.closed_ball 0 r)
begin intros z z_mem, apply differentiable_at.differentiable_within_at, have hu : is_unit (1 - z • a), { refine is_unit_one_sub_smul_of_lt_inv_radius (lt_of_le_of_lt (coe_mono _) hr), simpa only [norm_to_nnreal, real.to_nnreal_coe] using real.to_nnreal_mono (mem_closed_ball_zero_iff.mp z_mem) }, hav...
theorem
spectrum.differentiable_on_inverse_one_sub_smul
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "complete_space", "differentiable", "differentiable_at.comp", "differentiable_at.differentiable_within_at", "differentiable_at_inverse", "differentiable_on", "is_unit", "metric.closed_ball", "real.to_nnreal_coe", "real.to_nnreal_mono", "ring.inverse", "spectral_radius" ]
In a Banach algebra `A` over `𝕜`, for `a : A` the function `λ z, (1 - z • a)⁻¹` is differentiable on any closed ball centered at zero of radius `r < (spectral_radius 𝕜 a)⁻¹`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
limsup_pow_nnnorm_pow_one_div_le_spectral_radius (a : A) : limsup (λ n : ℕ, ↑‖a ^ n‖₊ ^ (1 / n : ℝ)) at_top ≤ spectral_radius ℂ a
begin refine ennreal.inv_le_inv.mp (le_of_forall_pos_nnreal_lt (λ r r_pos r_lt, _)), simp_rw [inv_limsup, ←one_div], let p : formal_multilinear_series ℂ ℂ A := λ n, continuous_multilinear_map.mk_pi_field ℂ (fin n) (a ^ n), suffices h : (r : ℝ≥0∞) ≤ p.radius, { convert h, simp only [p.radius_eq_liminf,...
lemma
spectrum.limsup_pow_nnnorm_pow_one_div_le_spectral_radius
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "continuous_multilinear_map.mk_pi_field", "ennreal.coe_rpow_def", "formal_multilinear_series", "has_fpower_series_on_ball", "spectral_radius" ]
The `limsup` relationship for the spectral radius used to prove `spectrum.gelfand_formula`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_nnnorm_pow_one_div_tendsto_nhds_spectral_radius (a : A) : tendsto (λ n : ℕ, ((‖a ^ n‖₊ ^ (1 / n : ℝ)) : ℝ≥0∞)) at_top (𝓝 (spectral_radius ℂ a))
tendsto_of_le_liminf_of_limsup_le (spectral_radius_le_liminf_pow_nnnorm_pow_one_div ℂ a) (limsup_pow_nnnorm_pow_one_div_le_spectral_radius a)
theorem
spectrum.pow_nnnorm_pow_one_div_tendsto_nhds_spectral_radius
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "spectral_radius", "tendsto_of_le_liminf_of_limsup_le" ]
**Gelfand's formula**: Given an element `a : A` of a complex Banach algebra, the `spectral_radius` of `a` is the limit of the sequence `‖a ^ n‖₊ ^ (1 / n)`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_norm_pow_one_div_tendsto_nhds_spectral_radius (a : A) : tendsto (λ n : ℕ, ennreal.of_real (‖a ^ n‖ ^ (1 / n : ℝ))) at_top (𝓝 (spectral_radius ℂ a))
begin convert pow_nnnorm_pow_one_div_tendsto_nhds_spectral_radius a, ext1, rw [←of_real_rpow_of_nonneg (norm_nonneg _) _, ←coe_nnnorm, coe_nnreal_eq], exact one_div_nonneg.mpr (by exact_mod_cast zero_le _), end
theorem
spectrum.pow_norm_pow_one_div_tendsto_nhds_spectral_radius
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "ennreal.of_real", "spectral_radius" ]
**Gelfand's formula**: Given an element `a : A` of a complex Banach algebra, the `spectral_radius` of `a` is the limit of the sequence `‖a ^ n‖₊ ^ (1 / n)`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty : (spectrum ℂ a).nonempty
begin /- Suppose `σ a = ∅`, then resolvent set is `ℂ`, any `(z • 1 - a)` is a unit, and `resolvent` is differentiable on `ℂ`. -/ rw set.nonempty_iff_ne_empty, by_contra h, have H₀ : resolvent_set ℂ a = set.univ, by rwa [spectrum, set.compl_empty_iff] at h, have H₁ : differentiable ℂ (λ z : ℂ, resolvent a z)...
theorem
spectrum.nonempty
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "by_contra", "differentiable", "differentiable_at", "em", "not_is_unit_zero", "real.norm_of_nonneg", "resolvent", "resolvent_set", "set.compl_empty_iff", "set.mem_univ", "set.nonempty_iff_ne_empty", "spectrum", "zero_lt_one" ]
In a (nontrivial) complex Banach algebra, every element has nonempty spectrum.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_nnnorm_eq_spectral_radius : ∃ z ∈ spectrum ℂ a, (‖z‖₊ : ℝ≥0∞) = spectral_radius ℂ a
exists_nnnorm_eq_spectral_radius_of_nonempty (spectrum.nonempty a)
lemma
spectrum.exists_nnnorm_eq_spectral_radius
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "spectral_radius", "spectrum", "spectrum.nonempty" ]
In a complex Banach algebra, the spectral radius is always attained by some element of the spectrum.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
spectral_radius_lt_of_forall_lt {r : ℝ≥0} (hr : ∀ z ∈ spectrum ℂ a, ‖z‖₊ < r) : spectral_radius ℂ a < r
spectral_radius_lt_of_forall_lt_of_nonempty (spectrum.nonempty a) hr
lemma
spectrum.spectral_radius_lt_of_forall_lt
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "spectral_radius", "spectrum", "spectrum.nonempty" ]
In a complex Banach algebra, if every element of the spectrum has norm strictly less than `r : ℝ≥0`, then the spectral radius is also strictly less than `r`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_polynomial_aeval (p : ℂ[X]) : spectrum ℂ (aeval a p) = (λ k, eval k p) '' (spectrum ℂ a)
map_polynomial_aeval_of_nonempty a p (spectrum.nonempty a)
lemma
spectrum.map_polynomial_aeval
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "spectrum", "spectrum.nonempty" ]
The **spectral mapping theorem** for polynomials in a Banach algebra over `ℂ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_pow (n : ℕ) : spectrum ℂ (a ^ n) = (λ x, x ^ n) '' (spectrum ℂ a)
by simpa only [aeval_X_pow, eval_pow, eval_X] using map_polynomial_aeval a (X ^ n)
lemma
spectrum.map_pow
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "map_pow", "spectrum" ]
A specialization of the spectral mapping theorem for polynomials in a Banach algebra over `ℂ` to monic monomials.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_eq_of_mem {a : A} {z : ℂ} (h : z ∈ σ a) : algebra_map ℂ A z = a
by rwa [mem_iff, hA, not_not, sub_eq_zero] at h
lemma
spectrum.algebra_map_eq_of_mem
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "algebra_map", "not_not" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.normed_ring.alg_equiv_complex_of_complete [complete_space A] : ℂ ≃ₐ[ℂ] A
let nt : nontrivial A := ⟨⟨1, 0, hA.mp ⟨⟨1, 1, mul_one _, mul_one _⟩, rfl⟩⟩⟩ in { to_fun := algebra_map ℂ A, inv_fun := λ a, (@spectrum.nonempty _ _ _ _ nt a).some, left_inv := λ z, by simpa only [@scalar_eq _ _ _ _ _ nt _] using (@spectrum.nonempty _ _ _ _ nt $ algebra_map ℂ A z).some_mem, right_inv := λ a, ...
def
normed_ring.alg_equiv_complex_of_complete
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "algebra.of_id", "algebra_map", "complete_space", "inv_fun", "mul_one", "nontrivial", "spectrum.nonempty" ]
**Gelfand-Mazur theorem**: For a complex Banach division algebra, the natural `algebra_map ℂ A` is an algebra isomorphism whose inverse is given by selecting the (unique) element of `spectrum ℂ a`. In addition, `algebra_map_isometry` guarantees this map is an isometry. Note: because `normed_division_ring` requires the...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exp_mem_exp [is_R_or_C 𝕜] [normed_ring A] [normed_algebra 𝕜 A] [complete_space A] (a : A) {z : 𝕜} (hz : z ∈ spectrum 𝕜 a) : exp 𝕜 z ∈ spectrum 𝕜 (exp 𝕜 a)
begin have hexpmul : exp 𝕜 a = exp 𝕜 (a - ↑ₐ z) * ↑ₐ (exp 𝕜 z), { rw [algebra_map_exp_comm z, ←exp_add_of_commute (algebra.commutes z (a - ↑ₐz)).symm, sub_add_cancel] }, let b := ∑' n : ℕ, ((n + 1).factorial⁻¹ : 𝕜) • (a - ↑ₐz) ^ n, have hb : summable (λ n : ℕ, ((n + 1).factorial⁻¹ : 𝕜) • (a - ↑ₐz) ^ ...
theorem
spectrum.exp_mem_exp
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "algebra.commutes", "algebra.smul_mul_assoc", "algebra_map_exp_comm", "commute.is_unit_mul_iff", "complete_space", "div_eq_mul_inv", "div_le_div", "exp", "exp_eq_tsum", "exp_series_summable'", "filter.eventually_cofinite_ne", "inv_one", "is_R_or_C", "is_R_or_C.norm_nat_cast", "is_unit.su...
For `𝕜 = ℝ` or `𝕜 = ℂ`, `exp 𝕜` maps the spectrum of `a` into the spectrum of `exp 𝕜 a`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_continuous_linear_map (φ : A →ₐ[𝕜] 𝕜) : A →L[𝕜] 𝕜
{ cont := map_continuous φ, .. φ.to_linear_map }
def
alg_hom.to_continuous_linear_map
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "cont" ]
An algebra homomorphism into the base field, as a continuous linear map (since it is automatically bounded).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_to_continuous_linear_map (φ : A →ₐ[𝕜] 𝕜) : ⇑φ.to_continuous_linear_map = φ
rfl
lemma
alg_hom.coe_to_continuous_linear_map
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_apply_le_self_mul_norm_one [alg_hom_class F 𝕜 A 𝕜] (f : F) (a : A) : ‖f a‖ ≤ ‖a‖ * ‖(1 : A)‖
spectrum.norm_le_norm_mul_of_mem (apply_mem_spectrum f _)
lemma
alg_hom.norm_apply_le_self_mul_norm_one
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "alg_hom_class", "spectrum.norm_le_norm_mul_of_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
norm_apply_le_self [norm_one_class A] [alg_hom_class F 𝕜 A 𝕜] (f : F) (a : A) : ‖f a‖ ≤ ‖a‖
spectrum.norm_le_norm_of_mem (apply_mem_spectrum f _)
lemma
alg_hom.norm_apply_le_self
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "alg_hom_class", "norm_one_class", "spectrum.norm_le_norm_of_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_continuous_linear_map_norm [norm_one_class A] (φ : A →ₐ[𝕜] 𝕜) : ‖φ.to_continuous_linear_map‖ = 1
continuous_linear_map.op_norm_eq_of_bounds zero_le_one (λ a, (one_mul ‖a‖).symm ▸ spectrum.norm_le_norm_of_mem (apply_mem_spectrum φ _)) (λ _ _ h, by simpa only [coe_to_continuous_linear_map, map_one, norm_one, mul_one] using h 1)
lemma
alg_hom.to_continuous_linear_map_norm
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "continuous_linear_map.op_norm_eq_of_bounds", "map_one", "mul_one", "norm_one_class", "one_mul", "spectrum.norm_le_norm_of_mem", "zero_le_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_alg_hom : (character_space 𝕜 A) ≃ (A →ₐ[𝕜] 𝕜)
{ to_fun := to_alg_hom, inv_fun := λ f, { val := f.to_continuous_linear_map, property := by { rw eq_set_map_one_map_mul, exact ⟨map_one f, map_mul f⟩ } }, left_inv := λ f, subtype.ext $ continuous_linear_map.ext $ λ x, rfl, right_inv := λ f, alg_hom.ext $ λ x, rfl }
def
weak_dual.character_space.equiv_alg_hom
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[ "alg_hom.ext", "continuous_linear_map.ext", "inv_fun", "map_mul", "subtype.ext" ]
The equivalence between characters and algebra homomorphisms into the base field.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_alg_hom_coe (f : character_space 𝕜 A) : ⇑(equiv_alg_hom f) = f
rfl
lemma
weak_dual.character_space.equiv_alg_hom_coe
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_alg_hom_symm_coe (f : A →ₐ[𝕜] 𝕜) : ⇑(equiv_alg_hom.symm f) = f
rfl
lemma
weak_dual.character_space.equiv_alg_hom_symm_coe
analysis.normed_space
src/analysis/normed_space/spectrum.lean
[ "field_theory.is_alg_closed.spectrum", "analysis.complex.liouville", "analysis.complex.polynomial", "analysis.analytic.radius_liminf", "topology.algebra.module.character_space", "analysis.normed_space.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_sum_fst_exp_series [field 𝕜] [ring R] [add_comm_group M] [algebra 𝕜 R] [module R M] [module Rᵐᵒᵖ M] [smul_comm_class R Rᵐᵒᵖ M] [module 𝕜 M] [is_scalar_tower 𝕜 R M] [is_scalar_tower 𝕜 Rᵐᵒᵖ M] [topological_ring R] [topological_add_group M] [has_continuous_smul R M] [has_continuous_smul Rᵐᵒᵖ M] (x : t...
by simpa [exp_series_apply_eq] using h
lemma
triv_sq_zero_ext.has_sum_fst_exp_series
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "add_comm_group", "algebra", "exp_series", "exp_series_apply_eq", "field", "has_continuous_smul", "has_sum", "is_scalar_tower", "module", "ring", "smul_comm_class", "topological_add_group", "topological_ring" ]
If `exp R x.fst` converges to `e` then `(exp R x).fst` converges to `e`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_sum_snd_exp_series_of_smul_comm [field 𝕜] [char_zero 𝕜] [ring R] [add_comm_group M] [algebra 𝕜 R] [module R M] [module Rᵐᵒᵖ M] [smul_comm_class R Rᵐᵒᵖ M] [module 𝕜 M] [is_scalar_tower 𝕜 R M] [is_scalar_tower 𝕜 Rᵐᵒᵖ M] [topological_ring R] [topological_add_group M] [has_continuous_smul R M] [has_cont...
begin simp_rw [exp_series_apply_eq] at *, conv { congr, funext, rw [snd_smul, snd_pow_of_smul_comm _ _ hx, nsmul_eq_smul_cast 𝕜 n, smul_smul, inv_mul_eq_div, ←inv_div, ←smul_assoc], }, apply has_sum.smul_const, rw [←has_sum_nat_add_iff' 1], swap, apply_instance, rw [finset.range_one, finset.s...
lemma
triv_sq_zero_ext.has_sum_snd_exp_series_of_smul_comm
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "add_comm_group", "algebra", "char_zero", "div_zero", "exp_series", "exp_series_apply_eq", "field", "finset.range_one", "has_continuous_smul", "has_sum", "has_sum.smul_const", "inv_mul_eq_div", "inv_zero", "is_scalar_tower", "module", "mul_div_cancel_left", "mul_opposite.op", "nat....
If `exp R x.fst` converges to `e` then `(exp R x).snd` converges to `e • x.snd`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_sum_exp_series_of_smul_comm [field 𝕜] [char_zero 𝕜] [ring R] [add_comm_group M] [algebra 𝕜 R] [module R M] [module Rᵐᵒᵖ M] [smul_comm_class R Rᵐᵒᵖ M] [module 𝕜 M] [is_scalar_tower 𝕜 R M] [is_scalar_tower 𝕜 Rᵐᵒᵖ M] [topological_ring R] [topological_add_group M] [has_continuous_smul R M] [has_continuo...
by simpa only [inl_fst_add_inr_snd_eq] using (has_sum_inl _ $ has_sum_fst_exp_series 𝕜 x h).add (has_sum_inr _ $ has_sum_snd_exp_series_of_smul_comm 𝕜 x hx h)
lemma
triv_sq_zero_ext.has_sum_exp_series_of_smul_comm
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "add_comm_group", "algebra", "char_zero", "exp_series", "field", "has_continuous_smul", "has_sum", "is_scalar_tower", "module", "mul_opposite.op", "ring", "smul_comm_class", "topological_add_group", "topological_ring" ]
If `exp R x.fst` converges to `e` then `exp R x` converges to `inl e + inr (e • x.snd)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exp_def_of_smul_comm (x : tsze R M) (hx : mul_opposite.op x.fst • x.snd = x.fst • x.snd) : exp 𝕜 x = inl (exp 𝕜 x.fst) + inr (exp 𝕜 x.fst • x.snd)
begin simp_rw [exp, formal_multilinear_series.sum], refine (has_sum_exp_series_of_smul_comm 𝕜 x hx _).tsum_eq, exact exp_series_has_sum_exp _, end
lemma
triv_sq_zero_ext.exp_def_of_smul_comm
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "exp", "exp_series_has_sum_exp", "formal_multilinear_series.sum", "mul_opposite.op" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exp_inl (x : R) : exp 𝕜 (inl x : tsze R M) = inl (exp 𝕜 x)
begin rw [exp_def_of_smul_comm, snd_inl, fst_inl, smul_zero, inr_zero, add_zero], { rw [snd_inl, fst_inl, smul_zero, smul_zero] } end
lemma
triv_sq_zero_ext.exp_inl
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "exp", "smul_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exp_inr (m : M) : exp 𝕜 (inr m : tsze R M) = 1 + inr m
begin rw [exp_def_of_smul_comm, snd_inr, fst_inr, exp_zero, one_smul, inl_one], { rw [snd_inr, fst_inr, mul_opposite.op_zero, zero_smul, zero_smul] } end
lemma
triv_sq_zero_ext.exp_inr
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "exp", "exp_zero", "mul_opposite.op_zero", "one_smul", "zero_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exp_def (x : tsze R M) : exp 𝕜 x = inl (exp 𝕜 x.fst) + inr (exp 𝕜 x.fst • x.snd)
exp_def_of_smul_comm 𝕜 x (op_smul_eq_smul _ _)
lemma
triv_sq_zero_ext.exp_def
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "exp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fst_exp (x : tsze R M) : fst (exp 𝕜 x) = exp 𝕜 x.fst
by rw [exp_def, fst_add, fst_inl, fst_inr, add_zero]
lemma
triv_sq_zero_ext.fst_exp
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "exp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
snd_exp (x : tsze R M) : snd (exp 𝕜 x) = exp 𝕜 x.fst • x.snd
by rw [exp_def, snd_add, snd_inl, snd_inr, zero_add]
lemma
triv_sq_zero_ext.snd_exp
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "exp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_smul_exp_of_invertible (x : tsze R M) [invertible x.fst] : x = x.fst • exp 𝕜 (⅟x.fst • inr x.snd)
by rw [←inr_smul, exp_inr, smul_add, ←inl_one, ←inl_smul, ←inr_smul, smul_eq_mul, mul_one, smul_smul, mul_inv_of_self, one_smul, inl_fst_add_inr_snd_eq]
lemma
triv_sq_zero_ext.eq_smul_exp_of_invertible
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "exp", "invertible", "mul_inv_of_self", "mul_one", "one_smul", "smul_add", "smul_eq_mul", "smul_smul" ]
Polar form of trivial-square-zero extension.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_smul_exp_of_ne_zero (x : tsze R M) (hx : x.fst ≠ 0) : x = x.fst • exp 𝕜 (x.fst⁻¹ • inr x.snd)
begin letI : invertible x.fst := invertible_of_nonzero hx, exact eq_smul_exp_of_invertible _ _ end
lemma
triv_sq_zero_ext.eq_smul_exp_of_ne_zero
analysis.normed_space
src/analysis/normed_space/triv_sq_zero_ext.lean
[ "analysis.normed_space.basic", "analysis.normed_space.exponential", "topology.instances.triv_sq_zero_ext" ]
[ "exp", "invertible", "invertible_of_nonzero" ]
More convenient version of `triv_sq_zero_ext.eq_smul_exp_of_invertible` for when `R` is a field.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_sub (t : R) (h : ‖t‖ < 1) : Rˣ
{ val := 1 - t, inv := ∑' n : ℕ, t ^ n, val_inv := mul_neg_geom_series t h, inv_val := geom_series_mul_neg t h }
def
units.one_sub
analysis.normed_space
src/analysis/normed_space/units.lean
[ "topology.algebra.ring.ideal", "analysis.specific_limits.normed" ]
[ "geom_series_mul_neg", "mul_neg_geom_series" ]
In a complete normed ring, a perturbation of `1` by an element `t` of distance less than `1` from `1` is a unit. Here we construct its `units` structure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add (x : Rˣ) (t : R) (h : ‖t‖ < ‖(↑x⁻¹ : R)‖⁻¹) : Rˣ
units.copy -- to make `coe_add` true definitionally, for convenience (x * (units.one_sub (-(↑x⁻¹ * t)) begin nontriviality R using [zero_lt_one], have hpos : 0 < ‖(↑x⁻¹ : R)‖ := units.norm_pos x⁻¹, calc ‖-(↑x⁻¹ * t)‖ = ‖↑x⁻¹ * t‖ : by { rw norm_neg } ... ≤ ‖(↑x⁻¹ ...
def
units.add
analysis.normed_space
src/analysis/normed_space/units.lean
[ "topology.algebra.ring.ideal", "analysis.specific_limits.normed" ]
[ "mul_inv_cancel", "norm_mul_le", "units.copy", "units.norm_pos", "units.one_sub", "zero_lt_one" ]
In a complete normed ring, a perturbation of a unit `x` by an element `t` of distance less than `‖x⁻¹‖⁻¹` from `x` is a unit. Here we construct its `units` structure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_of_nearby (x : Rˣ) (y : R) (h : ‖y - x‖ < ‖(↑x⁻¹ : R)‖⁻¹) : Rˣ
units.copy (x.add (y - x : R) h) y (by simp) _ rfl
def
units.unit_of_nearby
analysis.normed_space
src/analysis/normed_space/units.lean
[ "topology.algebra.ring.ideal", "analysis.specific_limits.normed" ]
[ "units.copy" ]
In a complete normed ring, an element `y` of distance less than `‖x⁻¹‖⁻¹` from `x` is a unit. Here we construct its `units` structure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open : is_open {x : R | is_unit x}
begin nontriviality R, apply metric.is_open_iff.mpr, rintros x' ⟨x, rfl⟩, refine ⟨‖(↑x⁻¹ : R)‖⁻¹, _root_.inv_pos.mpr (units.norm_pos x⁻¹), _⟩, intros y hy, rw [metric.mem_ball, dist_eq_norm] at hy, exact (x.unit_of_nearby y hy).is_unit end
lemma
units.is_open
analysis.normed_space
src/analysis/normed_space/units.lean
[ "topology.algebra.ring.ideal", "analysis.specific_limits.normed" ]
[ "is_open", "is_unit", "metric.mem_ball", "units.norm_pos" ]
The group of units of a complete normed ring is an open subset of the ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83