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concave_on_id {s : set β} (hs : convex 𝕜 s) : concave_on 𝕜 s id
⟨hs, by { intros, refl }⟩
lemma
concave_on_id
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.subset {t : set E} (hf : convex_on 𝕜 t f) (hst : s ⊆ t) (hs : convex 𝕜 s) : convex_on 𝕜 s f
⟨hs, λ x hx y hy, hf.2 (hst hx) (hst hy)⟩
lemma
convex_on.subset
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.subset {t : set E} (hf : concave_on 𝕜 t f) (hst : s ⊆ t) (hs : convex 𝕜 s) : concave_on 𝕜 s f
⟨hs, λ x hx y hy, hf.2 (hst hx) (hst hy)⟩
lemma
concave_on.subset
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.subset {t : set E} (hf : strict_convex_on 𝕜 t f) (hst : s ⊆ t) (hs : convex 𝕜 s) : strict_convex_on 𝕜 s f
⟨hs, λ x hx y hy, hf.2 (hst hx) (hst hy)⟩
lemma
strict_convex_on.subset
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.subset {t : set E} (hf : strict_concave_on 𝕜 t f) (hst : s ⊆ t) (hs : convex 𝕜 s) : strict_concave_on 𝕜 s f
⟨hs, λ x hx y hy, hf.2 (hst hx) (hst hy)⟩
lemma
strict_concave_on.subset
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "strict_concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.comp (hg : convex_on 𝕜 (f '' s) g) (hf : convex_on 𝕜 s f) (hg' : monotone_on g (f '' s)) : convex_on 𝕜 s (g ∘ f)
⟨hf.1, λ x hx y hy a b ha hb hab, (hg' (mem_image_of_mem f $ hf.1 hx hy ha hb hab) (hg.1 (mem_image_of_mem f hx) (mem_image_of_mem f hy) ha hb hab) $ hf.2 hx hy ha hb hab).trans $ hg.2 (mem_image_of_mem f hx) (mem_image_of_mem f hy) ha hb hab⟩
lemma
convex_on.comp
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "monotone_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.comp (hg : concave_on 𝕜 (f '' s) g) (hf : concave_on 𝕜 s f) (hg' : monotone_on g (f '' s)) : concave_on 𝕜 s (g ∘ f)
⟨hf.1, λ x hx y hy a b ha hb hab, (hg.2 (mem_image_of_mem f hx) (mem_image_of_mem f hy) ha hb hab).trans $ hg' (hg.1 (mem_image_of_mem f hx) (mem_image_of_mem f hy) ha hb hab) (mem_image_of_mem f $ hf.1 hx hy ha hb hab) $ hf.2 hx hy ha hb hab⟩
lemma
concave_on.comp
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "monotone_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.comp_concave_on (hg : convex_on 𝕜 (f '' s) g) (hf : concave_on 𝕜 s f) (hg' : antitone_on g (f '' s)) : convex_on 𝕜 s (g ∘ f)
hg.dual.comp hf hg'
lemma
convex_on.comp_concave_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "antitone_on", "concave_on", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.comp_convex_on (hg : concave_on 𝕜 (f '' s) g) (hf : convex_on 𝕜 s f) (hg' : antitone_on g (f '' s)) : concave_on 𝕜 s (g ∘ f)
hg.dual.comp hf hg'
lemma
concave_on.comp_convex_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "antitone_on", "concave_on", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.comp (hg : strict_convex_on 𝕜 (f '' s) g) (hf : strict_convex_on 𝕜 s f) (hg' : strict_mono_on g (f '' s)) (hf' : s.inj_on f) : strict_convex_on 𝕜 s (g ∘ f)
⟨hf.1, λ x hx y hy hxy a b ha hb hab, (hg' (mem_image_of_mem f $ hf.1 hx hy ha.le hb.le hab) (hg.1 (mem_image_of_mem f hx) (mem_image_of_mem f hy) ha.le hb.le hab) $ hf.2 hx hy hxy ha hb hab).trans $ hg.2 (mem_image_of_mem f hx) (mem_image_of_mem f hy) (mt (hf' hx hy) hxy) ha hb hab⟩
lemma
strict_convex_on.comp
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_convex_on", "strict_mono_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.comp (hg : strict_concave_on 𝕜 (f '' s) g) (hf : strict_concave_on 𝕜 s f) (hg' : strict_mono_on g (f '' s)) (hf' : s.inj_on f) : strict_concave_on 𝕜 s (g ∘ f)
⟨hf.1, λ x hx y hy hxy a b ha hb hab, (hg.2 (mem_image_of_mem f hx) (mem_image_of_mem f hy) (mt (hf' hx hy) hxy) ha hb hab).trans $ hg' (hg.1 (mem_image_of_mem f hx) (mem_image_of_mem f hy) ha.le hb.le hab) (mem_image_of_mem f $ hf.1 hx hy ha.le hb.le hab) $ hf.2 hx hy hxy ha hb hab⟩
lemma
strict_concave_on.comp
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_concave_on", "strict_mono_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.comp_strict_concave_on (hg : strict_convex_on 𝕜 (f '' s) g) (hf : strict_concave_on 𝕜 s f) (hg' : strict_anti_on g (f '' s)) (hf' : s.inj_on f) : strict_convex_on 𝕜 s (g ∘ f)
hg.dual.comp hf hg' hf'
lemma
strict_convex_on.comp_strict_concave_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_anti_on", "strict_concave_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.comp_strict_convex_on (hg : strict_concave_on 𝕜 (f '' s) g) (hf : strict_convex_on 𝕜 s f) (hg' : strict_anti_on g (f '' s)) (hf' : s.inj_on f) : strict_concave_on 𝕜 s (g ∘ f)
hg.dual.comp hf hg' hf'
lemma
strict_concave_on.comp_strict_convex_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_anti_on", "strict_concave_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.add (hf : convex_on 𝕜 s f) (hg : convex_on 𝕜 s g) : convex_on 𝕜 s (f + g)
⟨hf.1, λ x hx y hy a b ha hb hab, calc f (a • x + b • y) + g (a • x + b • y) ≤ (a • f x + b • f y) + (a • g x + b • g y) : add_le_add (hf.2 hx hy ha hb hab) (hg.2 hx hy ha hb hab) ... = a • (f x + g x) + b • (f y + g y) : by rw [smul_add, smul_add, add_add_add_comm]⟩
lemma
convex_on.add
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "smul_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.add (hf : concave_on 𝕜 s f) (hg : concave_on 𝕜 s g) : concave_on 𝕜 s (f + g)
hf.dual.add hg
lemma
concave_on.add
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on_const (c : β) (hs : convex 𝕜 s) : convex_on 𝕜 s (λ x:E, c)
⟨hs, λ x y _ _ a b _ _ hab, (convex.combo_self hab c).ge⟩
lemma
convex_on_const
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex.combo_self", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on_const (c : β) (hs : convex 𝕜 s) : concave_on 𝕜 s (λ x:E, c)
@convex_on_const _ _ βᵒᵈ _ _ _ _ _ _ c hs
lemma
concave_on_const
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex", "convex_on_const" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on_of_convex_epigraph (h : convex 𝕜 {p : E × β | p.1 ∈ s ∧ f p.1 ≤ p.2}) : convex_on 𝕜 s f
⟨λ x hx y hy a b ha hb hab, (@h (x, f x) ⟨hx, le_rfl⟩ (y, f y) ⟨hy, le_rfl⟩ a b ha hb hab).1, λ x hx y hy a b ha hb hab, (@h (x, f x) ⟨hx, le_rfl⟩ (y, f y) ⟨hy, le_rfl⟩ a b ha hb hab).2⟩
lemma
convex_on_of_convex_epigraph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on_of_convex_hypograph (h : convex 𝕜 {p : E × β | p.1 ∈ s ∧ p.2 ≤ f p.1}) : concave_on 𝕜 s f
@convex_on_of_convex_epigraph 𝕜 E βᵒᵈ _ _ _ _ _ _ _ h
lemma
concave_on_of_convex_hypograph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex", "convex_on_of_convex_epigraph" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.convex_le (hf : convex_on 𝕜 s f) (r : β) : convex 𝕜 {x ∈ s | f x ≤ r}
λ x hx y hy a b ha hb hab, ⟨hf.1 hx.1 hy.1 ha hb hab, calc f (a • x + b • y) ≤ a • f x + b • f y : hf.2 hx.1 hy.1 ha hb hab ... ≤ a • r + b • r : add_le_add (smul_le_smul_of_nonneg hx.2 ha) (smul_le_smul_of_nonneg hy.2 hb) ... =...
lemma
convex_on.convex_le
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex.combo_self", "convex_on", "smul_le_smul_of_nonneg" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.convex_ge (hf : concave_on 𝕜 s f) (r : β) : convex 𝕜 {x ∈ s | r ≤ f x}
hf.dual.convex_le r
lemma
concave_on.convex_ge
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.convex_epigraph (hf : convex_on 𝕜 s f) : convex 𝕜 {p : E × β | p.1 ∈ s ∧ f p.1 ≤ p.2}
begin rintro ⟨x, r⟩ ⟨hx, hr⟩ ⟨y, t⟩ ⟨hy, ht⟩ a b ha hb hab, refine ⟨hf.1 hx hy ha hb hab, _⟩, calc f (a • x + b • y) ≤ a • f x + b • f y : hf.2 hx hy ha hb hab ... ≤ a • r + b • t : add_le_add (smul_le_smul_of_nonneg hr ha) (smul_le_smul_of_nonneg ht hb) end
lemma
convex_on.convex_epigraph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex_on", "smul_le_smul_of_nonneg" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.convex_hypograph (hf : concave_on 𝕜 s f) : convex 𝕜 {p : E × β | p.1 ∈ s ∧ p.2 ≤ f p.1}
hf.dual.convex_epigraph
lemma
concave_on.convex_hypograph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on_iff_convex_epigraph : convex_on 𝕜 s f ↔ convex 𝕜 {p : E × β | p.1 ∈ s ∧ f p.1 ≤ p.2}
⟨convex_on.convex_epigraph, convex_on_of_convex_epigraph⟩
lemma
convex_on_iff_convex_epigraph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on_iff_convex_hypograph : concave_on 𝕜 s f ↔ convex 𝕜 {p : E × β | p.1 ∈ s ∧ p.2 ≤ f p.1}
@convex_on_iff_convex_epigraph 𝕜 E βᵒᵈ _ _ _ _ _ _ _ f
lemma
concave_on_iff_convex_hypograph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex", "convex_on_iff_convex_epigraph" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.translate_right (hf : convex_on 𝕜 s f) (c : E) : convex_on 𝕜 ((λ z, c + z) ⁻¹' s) (f ∘ (λ z, c + z))
⟨hf.1.translate_preimage_right _, λ x hx y hy a b ha hb hab, calc f (c + (a • x + b • y)) = f (a • (c + x) + b • (c + y)) : by rw [smul_add, smul_add, add_add_add_comm, convex.combo_self hab] ... ≤ a • f (c + x) + b • f (c + y) : hf.2 hx hy ha hb hab⟩
lemma
convex_on.translate_right
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex.combo_self", "convex_on", "smul_add" ]
Right translation preserves convexity.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.translate_right (hf : concave_on 𝕜 s f) (c : E) : concave_on 𝕜 ((λ z, c + z) ⁻¹' s) (f ∘ (λ z, c + z))
hf.dual.translate_right _
lemma
concave_on.translate_right
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
Right translation preserves concavity.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.translate_left (hf : convex_on 𝕜 s f) (c : E) : convex_on 𝕜 ((λ z, c + z) ⁻¹' s) (f ∘ (λ z, z + c))
by simpa only [add_comm] using hf.translate_right _
lemma
convex_on.translate_left
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on" ]
Left translation preserves convexity.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.translate_left (hf : concave_on 𝕜 s f) (c : E) : concave_on 𝕜 ((λ z, c + z) ⁻¹' s) (f ∘ (λ z, z + c))
hf.dual.translate_left _
lemma
concave_on.translate_left
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
Left translation preserves concavity.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on_iff_forall_pos {s : set E} {f : E → β} : convex_on 𝕜 s f ↔ convex 𝕜 s ∧ ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → f (a • x + b • y) ≤ a • f x + b • f y
begin refine and_congr_right' ⟨λ h x hx y hy a b ha hb hab, h hx hy ha.le hb.le hab, λ h x hx y hy a b ha hb hab, _⟩, obtain rfl | ha' := ha.eq_or_lt, { rw [zero_add] at hab, subst b, simp_rw [zero_smul, zero_add, one_smul] }, obtain rfl | hb' := hb.eq_or_lt, { rw [add_zero] at hab, subst a, simp_rw [zero...
lemma
convex_on_iff_forall_pos
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "and_congr_right'", "convex", "convex_on", "one_smul", "zero_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on_iff_forall_pos {s : set E} {f : E → β} : concave_on 𝕜 s f ↔ convex 𝕜 s ∧ ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → a • f x + b • f y ≤ f (a • x + b • y)
@convex_on_iff_forall_pos 𝕜 E βᵒᵈ _ _ _ _ _ _ _
lemma
concave_on_iff_forall_pos
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex", "convex_on_iff_forall_pos" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on_iff_pairwise_pos {s : set E} {f : E → β} : convex_on 𝕜 s f ↔ convex 𝕜 s ∧ s.pairwise (λ x y, ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → f (a • x + b • y) ≤ a • f x + b • f y)
begin rw convex_on_iff_forall_pos, refine and_congr_right' ⟨λ h x hx y hy _ a b ha hb hab, h hx hy ha hb hab, λ h x hx y hy a b ha hb hab, _⟩, obtain rfl | hxy := eq_or_ne x y, { rw [convex.combo_self hab, convex.combo_self hab] }, exact h hx hy hxy ha hb hab, end
lemma
convex_on_iff_pairwise_pos
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "and_congr_right'", "convex", "convex.combo_self", "convex_on", "convex_on_iff_forall_pos", "eq_or_ne" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on_iff_pairwise_pos {s : set E} {f : E → β} : concave_on 𝕜 s f ↔ convex 𝕜 s ∧ s.pairwise (λ x y, ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → a • f x + b • f y ≤ f (a • x + b • y))
@convex_on_iff_pairwise_pos 𝕜 E βᵒᵈ _ _ _ _ _ _ _
lemma
concave_on_iff_pairwise_pos
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex", "convex_on_iff_pairwise_pos" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_map.convex_on (f : E →ₗ[𝕜] β) {s : set E} (hs : convex 𝕜 s) : convex_on 𝕜 s f
⟨hs, λ _ _ _ _ _ _ _ _ _, by rw [f.map_add, f.map_smul, f.map_smul]⟩
lemma
linear_map.convex_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex_on" ]
A linear map is convex.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_map.concave_on (f : E →ₗ[𝕜] β) {s : set E} (hs : convex 𝕜 s) : concave_on 𝕜 s f
⟨hs, λ _ _ _ _ _ _ _ _ _, by rw [f.map_add, f.map_smul, f.map_smul]⟩
lemma
linear_map.concave_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex" ]
A linear map is concave.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.convex_on {s : set E} {f : E → β} (hf : strict_convex_on 𝕜 s f) : convex_on 𝕜 s f
convex_on_iff_pairwise_pos.mpr ⟨hf.1, λ x hx y hy hxy a b ha hb hab, (hf.2 hx hy hxy ha hb hab).le⟩
lemma
strict_convex_on.convex_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.concave_on {s : set E} {f : E → β} (hf : strict_concave_on 𝕜 s f) : concave_on 𝕜 s f
hf.dual.convex_on
lemma
strict_concave_on.concave_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "strict_concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.convex_lt (hf : strict_convex_on 𝕜 s f) (r : β) : convex 𝕜 {x ∈ s | f x < r}
convex_iff_pairwise_pos.2 $ λ x hx y hy hxy a b ha hb hab, ⟨hf.1 hx.1 hy.1 ha.le hb.le hab, calc f (a • x + b • y) < a • f x + b • f y : hf.2 hx.1 hy.1 hxy ha hb hab ... ≤ a • r + b • r : add_le_add (smul_lt_smul_of_pos hx.2 ha).le (smul_lt_smul_...
lemma
strict_convex_on.convex_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex.combo_self", "smul_lt_smul_of_pos", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.convex_gt (hf : strict_concave_on 𝕜 s f) (r : β) : convex 𝕜 {x ∈ s | r < f x}
hf.dual.convex_lt r
lemma
strict_concave_on.convex_gt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "strict_concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_order.convex_on_of_lt (hs : convex 𝕜 s) (hf : ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → x < y → ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → f (a • x + b • y) ≤ a • f x + b • f y) : convex_on 𝕜 s f
begin refine convex_on_iff_pairwise_pos.2 ⟨hs, λ x hx y hy hxy a b ha hb hab, _⟩, wlog h : x < y, { rw [add_comm (a • x), add_comm (a • f x)], rw add_comm at hab, refine this hs hf y hy x hx hxy.symm b a hb ha hab (hxy.lt_or_lt.resolve_left h), }, exact hf hx hy h ha hb hab, end
lemma
linear_order.convex_on_of_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex_on" ]
For a function on a convex set in a linearly ordered space (where the order and the algebraic structures aren't necessarily compatible), in order to prove that it is convex, it suffices to verify the inequality `f (a • x + b • y) ≤ a • f x + b • f y` only for `x < y` and positive `a`, `b`. The main use case is `E = 𝕜`...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_order.concave_on_of_lt (hs : convex 𝕜 s) (hf : ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → x < y → ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → a • f x + b • f y ≤ f (a • x + b • y)) : concave_on 𝕜 s f
@linear_order.convex_on_of_lt _ _ βᵒᵈ _ _ _ _ _ _ s f hs hf
lemma
linear_order.concave_on_of_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex", "linear_order.convex_on_of_lt" ]
For a function on a convex set in a linearly ordered space (where the order and the algebraic structures aren't necessarily compatible), in order to prove that it is concave it suffices to verify the inequality `a • f x + b • f y ≤ f (a • x + b • y)` for `x < y` and positive `a`, `b`. The main use case is `E = ℝ` howev...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_order.strict_convex_on_of_lt (hs : convex 𝕜 s) (hf : ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → x < y → ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → f (a • x + b • y) < a • f x + b • f y) : strict_convex_on 𝕜 s f
begin refine ⟨hs, λ x hx y hy hxy a b ha hb hab, _⟩, wlog h : x < y, { rw [add_comm (a • x), add_comm (a • f x)], rw add_comm at hab, refine this hs hf y hy x hx hxy.symm b a hb ha hab (hxy.lt_or_lt.resolve_left h), }, exact hf hx hy h ha hb hab, end
lemma
linear_order.strict_convex_on_of_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "strict_convex_on" ]
For a function on a convex set in a linearly ordered space (where the order and the algebraic structures aren't necessarily compatible), in order to prove that it is strictly convex, it suffices to verify the inequality `f (a • x + b • y) < a • f x + b • f y` for `x < y` and positive `a`, `b`. The main use case is `E =...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_order.strict_concave_on_of_lt (hs : convex 𝕜 s) (hf : ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → x < y → ∀ ⦃a b : 𝕜⦄, 0 < a → 0 < b → a + b = 1 → a • f x + b • f y < f (a • x + b • y)) : strict_concave_on 𝕜 s f
@linear_order.strict_convex_on_of_lt _ _ βᵒᵈ _ _ _ _ _ _ _ _ hs hf
lemma
linear_order.strict_concave_on_of_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "linear_order.strict_convex_on_of_lt", "strict_concave_on" ]
For a function on a convex set in a linearly ordered space (where the order and the algebraic structures aren't necessarily compatible), in order to prove that it is strictly concave it suffices to verify the inequality `a • f x + b • f y < f (a • x + b • y)` for `x < y` and positive `a`, `b`. The main use case is `E =...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.comp_linear_map {f : F → β} {s : set F} (hf : convex_on 𝕜 s f) (g : E →ₗ[𝕜] F) : convex_on 𝕜 (g ⁻¹' s) (f ∘ g)
⟨hf.1.linear_preimage _, λ x hx y hy a b ha hb hab, calc f (g (a • x + b • y)) = f (a • (g x) + b • (g y)) : by rw [g.map_add, g.map_smul, g.map_smul] ... ≤ a • f (g x) + b • f (g y) : hf.2 hx hy ha hb hab⟩
lemma
convex_on.comp_linear_map
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on" ]
If `g` is convex on `s`, so is `(f ∘ g)` on `f ⁻¹' s` for a linear `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.comp_linear_map {f : F → β} {s : set F} (hf : concave_on 𝕜 s f) (g : E →ₗ[𝕜] F) : concave_on 𝕜 (g ⁻¹' s) (f ∘ g)
hf.dual.comp_linear_map g
lemma
concave_on.comp_linear_map
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
If `g` is concave on `s`, so is `(g ∘ f)` on `f ⁻¹' s` for a linear `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.add_convex_on (hf : strict_convex_on 𝕜 s f) (hg : convex_on 𝕜 s g) : strict_convex_on 𝕜 s (f + g)
⟨hf.1, λ x hx y hy hxy a b ha hb hab, calc f (a • x + b • y) + g (a • x + b • y) < (a • f x + b • f y) + (a • g x + b • g y) : add_lt_add_of_lt_of_le (hf.2 hx hy hxy ha hb hab) (hg.2 hx hy ha.le hb.le hab) ... = a • (f x + g x) + b • (f y + g y) : by rw [smul_add, smul_add, add_add_add_comm]⟩
lemma
strict_convex_on.add_convex_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "smul_add", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.add_strict_convex_on (hf : convex_on 𝕜 s f) (hg : strict_convex_on 𝕜 s g) : strict_convex_on 𝕜 s (f + g)
(add_comm g f) ▸ hg.add_convex_on hf
lemma
convex_on.add_strict_convex_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.add (hf : strict_convex_on 𝕜 s f) (hg : strict_convex_on 𝕜 s g) : strict_convex_on 𝕜 s (f + g)
⟨hf.1, λ x hx y hy hxy a b ha hb hab, calc f (a • x + b • y) + g (a • x + b • y) < (a • f x + b • f y) + (a • g x + b • g y) : add_lt_add (hf.2 hx hy hxy ha hb hab) (hg.2 hx hy hxy ha hb hab) ... = a • (f x + g x) + b • (f y + g y) : by rw [smul_add, smul_add, add_add_add_comm]⟩
lemma
strict_convex_on.add
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "smul_add", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.add_concave_on (hf : strict_concave_on 𝕜 s f) (hg : concave_on 𝕜 s g) : strict_concave_on 𝕜 s (f + g)
hf.dual.add_convex_on hg.dual
lemma
strict_concave_on.add_concave_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "strict_concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.add_strict_concave_on (hf : concave_on 𝕜 s f) (hg : strict_concave_on 𝕜 s g) : strict_concave_on 𝕜 s (f + g)
hf.dual.add_strict_convex_on hg.dual
lemma
concave_on.add_strict_concave_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "strict_concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.add (hf : strict_concave_on 𝕜 s f) (hg : strict_concave_on 𝕜 s g) : strict_concave_on 𝕜 s (f + g)
hf.dual.add hg
lemma
strict_concave_on.add
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.convex_lt (hf : convex_on 𝕜 s f) (r : β) : convex 𝕜 {x ∈ s | f x < r}
convex_iff_forall_pos.2 $ λ x hx y hy a b ha hb hab, ⟨hf.1 hx.1 hy.1 ha.le hb.le hab, calc f (a • x + b • y) ≤ a • f x + b • f y : hf.2 hx.1 hy.1 ha.le hb.le hab ... < a • r + b • r : add_lt_add_of_lt_of_le (smul_lt_smul_of_pos hx.2 ha) (smul_le_smul_of_nonneg hy.2....
lemma
convex_on.convex_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex.combo_self", "convex_on", "smul_le_smul_of_nonneg", "smul_lt_smul_of_pos" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.convex_gt (hf : concave_on 𝕜 s f) (r : β) : convex 𝕜 {x ∈ s | r < f x}
hf.dual.convex_lt r
lemma
concave_on.convex_gt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.open_segment_subset_strict_epigraph (hf : convex_on 𝕜 s f) (p q : E × β) (hp : p.1 ∈ s ∧ f p.1 < p.2) (hq : q.1 ∈ s ∧ f q.1 ≤ q.2) : open_segment 𝕜 p q ⊆ {p : E × β | p.1 ∈ s ∧ f p.1 < p.2}
begin rintro _ ⟨a, b, ha, hb, hab, rfl⟩, refine ⟨hf.1 hp.1 hq.1 ha.le hb.le hab, _⟩, calc f (a • p.1 + b • q.1) ≤ a • f p.1 + b • f q.1 : hf.2 hp.1 hq.1 ha.le hb.le hab ... < a • p.2 + b • q.2 : add_lt_add_of_lt_of_le (smul_lt_smul_of_pos hp.2 ha) (smul_le_smul_of_nonneg hq.2 hb.le) end
lemma
convex_on.open_segment_subset_strict_epigraph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "open_segment", "smul_le_smul_of_nonneg", "smul_lt_smul_of_pos" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.open_segment_subset_strict_hypograph (hf : concave_on 𝕜 s f) (p q : E × β) (hp : p.1 ∈ s ∧ p.2 < f p.1) (hq : q.1 ∈ s ∧ q.2 ≤ f q.1) : open_segment 𝕜 p q ⊆ {p : E × β | p.1 ∈ s ∧ p.2 < f p.1}
hf.dual.open_segment_subset_strict_epigraph p q hp hq
lemma
concave_on.open_segment_subset_strict_hypograph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.convex_strict_epigraph (hf : convex_on 𝕜 s f) : convex 𝕜 {p : E × β | p.1 ∈ s ∧ f p.1 < p.2}
convex_iff_open_segment_subset.mpr $ λ p hp q hq, hf.open_segment_subset_strict_epigraph p q hp ⟨hq.1, hq.2.le⟩
lemma
convex_on.convex_strict_epigraph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.convex_strict_hypograph (hf : concave_on 𝕜 s f) : convex 𝕜 {p : E × β | p.1 ∈ s ∧ p.2 < f p.1}
hf.dual.convex_strict_epigraph
lemma
concave_on.convex_strict_hypograph
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.sup (hf : convex_on 𝕜 s f) (hg : convex_on 𝕜 s g) : convex_on 𝕜 s (f ⊔ g)
begin refine ⟨hf.left, λ x hx y hy a b ha hb hab, sup_le _ _⟩, { calc f (a • x + b • y) ≤ a • f x + b • f y : hf.right hx hy ha hb hab ... ≤ a • (f x ⊔ g x) + b • (f y ⊔ g y) : add_le_add (smul_le_smul_of_nonneg le_sup_left ha) (smul_le_smul_of_nonneg le_sup_left hb) }, { calc g (...
lemma
convex_on.sup
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "le_sup_left", "le_sup_right", "smul_le_smul_of_nonneg", "sup_le" ]
The pointwise maximum of convex functions is convex.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.inf (hf : concave_on 𝕜 s f) (hg : concave_on 𝕜 s g) : concave_on 𝕜 s (f ⊓ g)
hf.dual.sup hg
lemma
concave_on.inf
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
The pointwise minimum of concave functions is concave.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.sup (hf : strict_convex_on 𝕜 s f) (hg : strict_convex_on 𝕜 s g) : strict_convex_on 𝕜 s (f ⊔ g)
⟨hf.left, λ x hx y hy hxy a b ha hb hab, max_lt (calc f (a • x + b • y) < a • f x + b • f y : hf.2 hx hy hxy ha hb hab ... ≤ a • (f x ⊔ g x) + b • (f y ⊔ g y) : add_le_add (smul_le_smul_of_nonneg le_sup_left ha.le) (smul_le_smul_of_nonneg le_sup_left hb.le)) (calc g (a • x + b • y) < a...
lemma
strict_convex_on.sup
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "le_sup_left", "le_sup_right", "smul_le_smul_of_nonneg", "strict_convex_on" ]
The pointwise maximum of strictly convex functions is strictly convex.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.inf (hf : strict_concave_on 𝕜 s f) (hg : strict_concave_on 𝕜 s g) : strict_concave_on 𝕜 s (f ⊓ g)
hf.dual.sup hg
lemma
strict_concave_on.inf
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_concave_on" ]
The pointwise minimum of strictly concave functions is strictly concave.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.le_on_segment' (hf : convex_on 𝕜 s f) {x y : E} (hx : x ∈ s) (hy : y ∈ s) {a b : 𝕜} (ha : 0 ≤ a) (hb : 0 ≤ b) (hab : a + b = 1) : f (a • x + b • y) ≤ max (f x) (f y)
calc f (a • x + b • y) ≤ a • f x + b • f y : hf.2 hx hy ha hb hab ... ≤ a • max (f x) (f y) + b • max (f x) (f y) : add_le_add (smul_le_smul_of_nonneg (le_max_left _ _) ha) (smul_le_smul_of_nonneg (le_max_right _ _) hb) ... = max (f x) (f y) : convex.combo_self hab _
lemma
convex_on.le_on_segment'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex.combo_self", "convex_on", "smul_le_smul_of_nonneg" ]
A convex function on a segment is upper-bounded by the max of its endpoints.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.ge_on_segment' (hf : concave_on 𝕜 s f) {x y : E} (hx : x ∈ s) (hy : y ∈ s) {a b : 𝕜} (ha : 0 ≤ a) (hb : 0 ≤ b) (hab : a + b = 1) : min (f x) (f y) ≤ f (a • x + b • y)
hf.dual.le_on_segment' hx hy ha hb hab
lemma
concave_on.ge_on_segment'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
A concave function on a segment is lower-bounded by the min of its endpoints.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.le_on_segment (hf : convex_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ [x -[𝕜] y]) : f z ≤ max (f x) (f y)
let ⟨a, b, ha, hb, hab, hz⟩ := hz in hz ▸ hf.le_on_segment' hx hy ha hb hab
lemma
convex_on.le_on_segment
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on" ]
A convex function on a segment is upper-bounded by the max of its endpoints.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.ge_on_segment (hf : concave_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ [x -[𝕜] y]) : min (f x) (f y) ≤ f z
hf.dual.le_on_segment hx hy hz
lemma
concave_on.ge_on_segment
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
A concave function on a segment is lower-bounded by the min of its endpoints.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.lt_on_open_segment' (hf : strict_convex_on 𝕜 s f) {x y : E} (hx : x ∈ s) (hy : y ∈ s) (hxy : x ≠ y) {a b : 𝕜} (ha : 0 < a) (hb : 0 < b) (hab : a + b = 1) : f (a • x + b • y) < max (f x) (f y)
calc f (a • x + b • y) < a • f x + b • f y : hf.2 hx hy hxy ha hb hab ... ≤ a • max (f x) (f y) + b • max (f x) (f y) : add_le_add (smul_le_smul_of_nonneg (le_max_left _ _) ha.le) (smul_le_smul_of_nonneg (le_max_right _ _) hb.le) ... = max (f x) (f y) : convex.combo_self hab _
lemma
strict_convex_on.lt_on_open_segment'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex.combo_self", "smul_le_smul_of_nonneg", "strict_convex_on" ]
A strictly convex function on an open segment is strictly upper-bounded by the max of its endpoints.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.lt_on_open_segment' (hf : strict_concave_on 𝕜 s f) {x y : E} (hx : x ∈ s) (hy : y ∈ s) (hxy : x ≠ y) {a b : 𝕜} (ha : 0 < a) (hb : 0 < b) (hab : a + b = 1) : min (f x) (f y) < f (a • x + b • y)
hf.dual.lt_on_open_segment' hx hy hxy ha hb hab
lemma
strict_concave_on.lt_on_open_segment'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_concave_on" ]
A strictly concave function on an open segment is strictly lower-bounded by the min of its endpoints.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.lt_on_open_segment (hf : strict_convex_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hxy : x ≠ y) (hz : z ∈ open_segment 𝕜 x y) : f z < max (f x) (f y)
let ⟨a, b, ha, hb, hab, hz⟩ := hz in hz ▸ hf.lt_on_open_segment' hx hy hxy ha hb hab
lemma
strict_convex_on.lt_on_open_segment
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "open_segment", "strict_convex_on" ]
A strictly convex function on an open segment is strictly upper-bounded by the max of its endpoints.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.lt_on_open_segment (hf : strict_concave_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hxy : x ≠ y) (hz : z ∈ open_segment 𝕜 x y) : min (f x) (f y) < f z
hf.dual.lt_on_open_segment hx hy hxy hz
lemma
strict_concave_on.lt_on_open_segment
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "open_segment", "strict_concave_on" ]
A strictly concave function on an open segment is strictly lower-bounded by the min of its endpoints.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.le_left_of_right_le' (hf : convex_on 𝕜 s f) {x y : E} (hx : x ∈ s) (hy : y ∈ s) {a b : 𝕜} (ha : 0 < a) (hb : 0 ≤ b) (hab : a + b = 1) (hfy : f y ≤ f (a • x + b • y)) : f (a • x + b • y) ≤ f x
le_of_not_lt $ λ h, lt_irrefl (f (a • x + b • y)) $ calc f (a • x + b • y) ≤ a • f x + b • f y : hf.2 hx hy ha.le hb hab ... < a • f (a • x + b • y) + b • f (a • x + b • y) : add_lt_add_of_lt_of_le (smul_lt_smul_of_pos h ha) (smul_le_smul_of_nonneg hfy hb) ... = f (a • x + b • y) : convex....
lemma
convex_on.le_left_of_right_le'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex.combo_self", "convex_on", "smul_le_smul_of_nonneg", "smul_lt_smul_of_pos" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.left_le_of_le_right' (hf : concave_on 𝕜 s f) {x y : E} (hx : x ∈ s) (hy : y ∈ s) {a b : 𝕜} (ha : 0 < a) (hb : 0 ≤ b) (hab : a + b = 1) (hfy : f (a • x + b • y) ≤ f y) : f x ≤ f (a • x + b • y)
hf.dual.le_left_of_right_le' hx hy ha hb hab hfy
lemma
concave_on.left_le_of_le_right'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.le_right_of_left_le' (hf : convex_on 𝕜 s f) {x y : E} {a b : 𝕜} (hx : x ∈ s) (hy : y ∈ s) (ha : 0 ≤ a) (hb : 0 < b) (hab : a + b = 1) (hfx : f x ≤ f (a • x + b • y)) : f (a • x + b • y) ≤ f y
begin rw add_comm at ⊢ hab hfx, exact hf.le_left_of_right_le' hy hx hb ha hab hfx, end
lemma
convex_on.le_right_of_left_le'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.right_le_of_le_left' (hf : concave_on 𝕜 s f) {x y : E} {a b : 𝕜} (hx : x ∈ s) (hy : y ∈ s) (ha : 0 ≤ a) (hb : 0 < b) (hab : a + b = 1) (hfx : f (a • x + b • y) ≤ f x) : f y ≤ f (a • x + b • y)
hf.dual.le_right_of_left_le' hx hy ha hb hab hfx
lemma
concave_on.right_le_of_le_left'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.le_left_of_right_le (hf : convex_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ open_segment 𝕜 x y) (hyz : f y ≤ f z) : f z ≤ f x
begin obtain ⟨a, b, ha, hb, hab, rfl⟩ := hz, exact hf.le_left_of_right_le' hx hy ha hb.le hab hyz, end
lemma
convex_on.le_left_of_right_le
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.left_le_of_le_right (hf : concave_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ open_segment 𝕜 x y) (hyz : f z ≤ f y) : f x ≤ f z
hf.dual.le_left_of_right_le hx hy hz hyz
lemma
concave_on.left_le_of_le_right
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.le_right_of_left_le (hf : convex_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ open_segment 𝕜 x y) (hxz : f x ≤ f z) : f z ≤ f y
begin obtain ⟨a, b, ha, hb, hab, rfl⟩ := hz, exact hf.le_right_of_left_le' hx hy ha.le hb hab hxz, end
lemma
convex_on.le_right_of_left_le
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.right_le_of_le_left (hf : concave_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ open_segment 𝕜 x y) (hxz : f z ≤ f x) : f y ≤ f z
hf.dual.le_right_of_left_le hx hy hz hxz
lemma
concave_on.right_le_of_le_left
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.lt_left_of_right_lt' (hf : convex_on 𝕜 s f) {x y : E} (hx : x ∈ s) (hy : y ∈ s) {a b : 𝕜} (ha : 0 < a) (hb : 0 < b) (hab : a + b = 1) (hfy : f y < f (a • x + b • y)) : f (a • x + b • y) < f x
not_le.1 $ λ h, lt_irrefl (f (a • x + b • y)) $ calc f (a • x + b • y) ≤ a • f x + b • f y : hf.2 hx hy ha.le hb.le hab ... < a • f (a • x + b • y) + b • f (a • x + b • y) : add_lt_add_of_le_of_lt (smul_le_smul_of_nonneg h ha.le) (smul_lt_smul_of_pos hfy hb) ... = f (a • x + b • y) : conve...
lemma
convex_on.lt_left_of_right_lt'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex.combo_self", "convex_on", "smul_le_smul_of_nonneg", "smul_lt_smul_of_pos" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.left_lt_of_lt_right' (hf : concave_on 𝕜 s f) {x y : E} (hx : x ∈ s) (hy : y ∈ s) {a b : 𝕜} (ha : 0 < a) (hb : 0 < b) (hab : a + b = 1) (hfy : f (a • x + b • y) < f y) : f x < f (a • x + b • y)
hf.dual.lt_left_of_right_lt' hx hy ha hb hab hfy
lemma
concave_on.left_lt_of_lt_right'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.lt_right_of_left_lt' (hf : convex_on 𝕜 s f) {x y : E} {a b : 𝕜} (hx : x ∈ s) (hy : y ∈ s) (ha : 0 < a) (hb : 0 < b) (hab : a + b = 1) (hfx : f x < f (a • x + b • y)) : f (a • x + b • y) < f y
begin rw add_comm at ⊢ hab hfx, exact hf.lt_left_of_right_lt' hy hx hb ha hab hfx, end
lemma
convex_on.lt_right_of_left_lt'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.lt_right_of_left_lt' (hf : concave_on 𝕜 s f) {x y : E} {a b : 𝕜} (hx : x ∈ s) (hy : y ∈ s) (ha : 0 < a) (hb : 0 < b) (hab : a + b = 1) (hfx : f (a • x + b • y) < f x) : f y < f (a • x + b • y)
hf.dual.lt_right_of_left_lt' hx hy ha hb hab hfx
lemma
concave_on.lt_right_of_left_lt'
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.lt_left_of_right_lt (hf : convex_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ open_segment 𝕜 x y) (hyz : f y < f z) : f z < f x
begin obtain ⟨a, b, ha, hb, hab, rfl⟩ := hz, exact hf.lt_left_of_right_lt' hx hy ha hb hab hyz, end
lemma
convex_on.lt_left_of_right_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.left_lt_of_lt_right (hf : concave_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ open_segment 𝕜 x y) (hyz : f z < f y) : f x < f z
hf.dual.lt_left_of_right_lt hx hy hz hyz
lemma
concave_on.left_lt_of_lt_right
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.lt_right_of_left_lt (hf : convex_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ open_segment 𝕜 x y) (hxz : f x < f z) : f z < f y
begin obtain ⟨a, b, ha, hb, hab, rfl⟩ := hz, exact hf.lt_right_of_left_lt' hx hy ha hb hab hxz, end
lemma
convex_on.lt_right_of_left_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.lt_right_of_left_lt (hf : concave_on 𝕜 s f) {x y z : E} (hx : x ∈ s) (hy : y ∈ s) (hz : z ∈ open_segment 𝕜 x y) (hxz : f z < f x) : f y < f z
hf.dual.lt_right_of_left_lt hx hy hz hxz
lemma
concave_on.lt_right_of_left_lt
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "open_segment" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_convex_on_iff : convex_on 𝕜 s (-f) ↔ concave_on 𝕜 s f
begin split, { rintro ⟨hconv, h⟩, refine ⟨hconv, λ x hx y hy a b ha hb hab, _⟩, simp [neg_apply, neg_le, add_comm] at h, exact h hx hy ha hb hab }, { rintro ⟨hconv, h⟩, refine ⟨hconv, λ x hx y hy a b ha hb hab, _⟩, rw ←neg_le_neg_iff, simp_rw [neg_add, pi.neg_apply, smul_neg, neg_neg], ...
lemma
neg_convex_on_iff
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex_on", "smul_neg" ]
A function `-f` is convex iff `f` is concave.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_concave_on_iff : concave_on 𝕜 s (-f) ↔ convex_on 𝕜 s f
by rw [← neg_convex_on_iff, neg_neg f]
lemma
neg_concave_on_iff
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex_on", "neg_convex_on_iff" ]
A function `-f` is concave iff `f` is convex.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_strict_convex_on_iff : strict_convex_on 𝕜 s (-f) ↔ strict_concave_on 𝕜 s f
begin split, { rintro ⟨hconv, h⟩, refine ⟨hconv, λ x hx y hy hxy a b ha hb hab, _⟩, simp [neg_apply, neg_lt, add_comm] at h, exact h hx hy hxy ha hb hab }, { rintro ⟨hconv, h⟩, refine ⟨hconv, λ x hx y hy hxy a b ha hb hab, _⟩, rw ←neg_lt_neg_iff, simp_rw [neg_add, pi.neg_apply, smul_neg, n...
lemma
neg_strict_convex_on_iff
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "smul_neg", "strict_concave_on", "strict_convex_on" ]
A function `-f` is strictly convex iff `f` is strictly concave.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_strict_concave_on_iff : strict_concave_on 𝕜 s (-f) ↔ strict_convex_on 𝕜 s f
by rw [← neg_strict_convex_on_iff, neg_neg f]
lemma
neg_strict_concave_on_iff
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "neg_strict_convex_on_iff", "strict_concave_on", "strict_convex_on" ]
A function `-f` is strictly concave iff `f` is strictly convex.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.sub (hf : convex_on 𝕜 s f) (hg : concave_on 𝕜 s g) : convex_on 𝕜 s (f - g)
(sub_eq_add_neg f g).symm ▸ hf.add hg.neg
lemma
convex_on.sub
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.sub (hf : concave_on 𝕜 s f) (hg : convex_on 𝕜 s g) : concave_on 𝕜 s (f - g)
(sub_eq_add_neg f g).symm ▸ hf.add hg.neg
lemma
concave_on.sub
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.sub (hf : strict_convex_on 𝕜 s f) (hg : strict_concave_on 𝕜 s g) : strict_convex_on 𝕜 s (f - g)
(sub_eq_add_neg f g).symm ▸ hf.add hg.neg
lemma
strict_convex_on.sub
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_concave_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.sub (hf : strict_concave_on 𝕜 s f) (hg : strict_convex_on 𝕜 s g) : strict_concave_on 𝕜 s (f - g)
(sub_eq_add_neg f g).symm ▸ hf.add hg.neg
lemma
strict_concave_on.sub
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_concave_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convex_on.sub_strict_concave_on (hf : convex_on 𝕜 s f) (hg : strict_concave_on 𝕜 s g) : strict_convex_on 𝕜 s (f - g)
(sub_eq_add_neg f g).symm ▸ hf.add_strict_convex_on hg.neg
lemma
convex_on.sub_strict_concave_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "strict_concave_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
concave_on.sub_strict_convex_on (hf : concave_on 𝕜 s f) (hg : strict_convex_on 𝕜 s g) : strict_concave_on 𝕜 s (f - g)
(sub_eq_add_neg f g).symm ▸ hf.add_strict_concave_on hg.neg
lemma
concave_on.sub_strict_convex_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "strict_concave_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.sub_concave_on (hf : strict_convex_on 𝕜 s f) (hg : concave_on 𝕜 s g) : strict_convex_on 𝕜 s (f - g)
(sub_eq_add_neg f g).symm ▸ hf.add_convex_on hg.neg
lemma
strict_convex_on.sub_concave_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "concave_on", "strict_convex_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.sub_convex_on (hf : strict_concave_on 𝕜 s f) (hg : convex_on 𝕜 s g) : strict_concave_on 𝕜 s (f - g)
(sub_eq_add_neg f g).symm ▸ hf.add_concave_on hg.neg
lemma
strict_concave_on.sub_convex_on
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex_on", "strict_concave_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.translate_right (hf : strict_convex_on 𝕜 s f) (c : E) : strict_convex_on 𝕜 ((λ z, c + z) ⁻¹' s) (f ∘ (λ z, c + z))
⟨hf.1.translate_preimage_right _, λ x hx y hy hxy a b ha hb hab, calc f (c + (a • x + b • y)) = f (a • (c + x) + b • (c + y)) : by rw [smul_add, smul_add, add_add_add_comm, convex.combo_self hab] ... < a • f (c + x) + b • f (c + y) : hf.2 hx hy ((add_right_injective c).ne hxy) ha hb hab⟩
lemma
strict_convex_on.translate_right
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "convex.combo_self", "smul_add", "strict_convex_on" ]
Right translation preserves strict convexity.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_concave_on.translate_right (hf : strict_concave_on 𝕜 s f) (c : E) : strict_concave_on 𝕜 ((λ z, c + z) ⁻¹' s) (f ∘ (λ z, c + z))
hf.dual.translate_right _
lemma
strict_concave_on.translate_right
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_concave_on" ]
Right translation preserves strict concavity.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
strict_convex_on.translate_left (hf : strict_convex_on 𝕜 s f) (c : E) : strict_convex_on 𝕜 ((λ z, c + z) ⁻¹' s) (f ∘ (λ z, z + c))
by simpa only [add_comm] using hf.translate_right _
lemma
strict_convex_on.translate_left
analysis.convex
src/analysis/convex/function.lean
[ "analysis.convex.basic" ]
[ "strict_convex_on" ]
Left translation preserves strict convexity.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83