Documentation

MiscYD.Mathlib.Analysis.Convex.Combination

theorem mem_convexHull_image {ι : Type u_1} {R : Type u_2} {E : Type u_3} [Field R] [LinearOrder R] [IsStrictOrderedRing R] [AddCommGroup E] [Module R E] {s : Finset ι} {f : ιE} {x : E} :
x (convexHull R) (f '' s) ∃ (w : ιR), (∀ is, 0 w i) is, w i = 1 s.centerMass w f = x
theorem centerMass_congr {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s t : Finset ι} {v w : ι𝕜} {x y : ιV} (hst : s = t) (hvw : it, v i = w i) (hxy : it, x i = y i) :
s.centerMass v x = t.centerMass w y
theorem centerMass_union {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s t : Finset ι} {w : ι𝕜} {x : ιV} [DecidableEq ι] (hst : Disjoint s t) (hs : (∀ is, w i = 0) is, w i 0) (ht : (∀ it, w i = 0) it, w i 0) (hw₁ : is t, w i = 1) :
(s t).centerMass w x = (∑ is, w i) s.centerMass w x + (∑ it, w i) t.centerMass w x
theorem centerMass_union_of_ne_zero {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s t : Finset ι} {w : ι𝕜} {x : ιV} [DecidableEq ι] (hst : Disjoint s t) (hs : is, w i 0) (ht : it, w i 0) (hw₁ : is t, w i = 1) :
(s t).centerMass w x = (∑ is, w i) s.centerMass w x + (∑ it, w i) t.centerMass w x
theorem lineMap_centerMass_centerMass {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s t : Finset ι} {w : ι𝕜} {x : ιV} [DecidableEq ι] (hst : Disjoint s t) (hs : (∀ is, w i = 0) is, w i 0) (ht : (∀ it, w i = 0) it, w i 0) (hw₁ : is t, w i = 1) :
(AffineMap.lineMap (s.centerMass w x) (t.centerMass w x)) (∑ it, w i) = (s t).centerMass w x
theorem lineMap_centerMass_centerMass_of_ne_zero {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s t : Finset ι} {w : ι𝕜} {x : ιV} [DecidableEq ι] (hst : Disjoint s t) (hs : is, w i 0) (ht : it, w i 0) (hw₁ : is t, w i = 1) :
(AffineMap.lineMap (s.centerMass w x) (t.centerMass w x)) (∑ it, w i) = (s t).centerMass w x
theorem lineMap_centerMass_sdiff {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s : Finset ι} {w : ι𝕜} {x : ιV} {i : ι} [DecidableEq ι] (hi : i s) (hi₀ : w i 0) (hi₁ : w i 1) (hw₁ : is, w i = 1) :
(AffineMap.lineMap ((s \ {i}).centerMass w x) (x i)) (w i) = s.centerMass w x
theorem centerMass_sdiff_of_weight_eq_zero {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s : Finset ι} {w : ι𝕜} {x : ιV} {i : ι} [DecidableEq ι] (hi : i s) (hi₀ : w i = 0) :
(s \ {i}).centerMass w x = s.centerMass w x
theorem lineMap_centerMass_sdiff_singleton_of_ne_one {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s : Finset ι} {w : ι𝕜} {x : ιV} {i : ι} [DecidableEq ι] (hi : i s) (hi₁ : w i 1) (hw₁ : js, w j = 1) :
(AffineMap.lineMap ((s \ {i}).centerMass w x) (x i)) (w i) = s.centerMass w x
theorem centerMass_union_of_nonneg {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s t : Finset ι} {w : ι𝕜} {x : ιV} [DecidableEq ι] [LinearOrder 𝕜] [IsStrictOrderedRing 𝕜] (hst : Disjoint s t) (hw₀ : is t, 0 w i) (hw₁ : is t, w i = 1) :
(s t).centerMass w x = (∑ is, w i) s.centerMass w x + (∑ it, w i) t.centerMass w x
theorem lineMap_centerMass_centerMass_of_nonneg {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s t : Finset ι} {w : ι𝕜} {x : ιV} [DecidableEq ι] [LinearOrder 𝕜] [IsStrictOrderedRing 𝕜] (hst : Disjoint s t) (hw₀ : is t, 0 w i) (hw₁ : is t, w i = 1) :
(AffineMap.lineMap (s.centerMass w x) (t.centerMass w x)) (∑ it, w i) = (s t).centerMass w x
theorem lineMap_centerMass_sdiff_singleton_of_nonneg {ι : Type u_1} {𝕜 : Type u_2} {V : Type u_3} [Field 𝕜] [AddCommGroup V] [Module 𝕜 V] {s : Finset ι} {w : ι𝕜} {x : ιV} {i : ι} [DecidableEq ι] [LinearOrder 𝕜] [IsStrictOrderedRing 𝕜] (hi : i s) (hw₀ : js \ {i}, 0 w j) (hw₁ : js, w j = 1) :
(AffineMap.lineMap ((s \ {i}).centerMass w x) (x i)) (w i) = s.centerMass w x