Documentation

MeanFourier.Mathlib.Combinatorics.Additive.CovBySMul

TODO #

Protected CovBySMul.rfl

theorem CovBySMul.pos {M : Type u_1} {X : Type u_3} [Monoid M] [MulAction M X] {A B : Set X} {K : } (hAB : CovBySMul M K A B) (hA : A.Nonempty) :
0 < K
theorem CovByVAdd.pos {M : Type u_1} {X : Type u_3} [AddMonoid M] [AddAction M X] {A B : Set X} {K : } (hAB : CovByVAdd M K A B) (hA : A.Nonempty) :
0 < K
theorem CovBySMul.prod {M : Type u_1} [Monoid M] {K L : } {N : Type u_4} [Group N] {A B : Set M} {C D : Set N} (hAB : CovBySMul M K A B) (hCD : CovBySMul N L C D) :
CovBySMul (M × N) (K * L) (A ×ˢ C) (B ×ˢ D)
theorem CovByVAdd.sum {M : Type u_1} [AddMonoid M] {K L : } {N : Type u_4} [AddGroup N] {A B : Set M} {C D : Set N} (hAB : CovByVAdd M K A B) (hCD : CovByVAdd N L C D) :
CovByVAdd (M × N) (K * L) (A ×ˢ C) (B ×ˢ D)
theorem CovBySMul.pi {ι : Type u_4} {G : ιType u_5} {X : ιType u_6} {s : Finset ι} [(i : ι) → Group (G i)] [(i : ι) → MulAction (G i) (X i)] {A B : (i : ι) → Set (X i)} {K : ι} (hAB : is, CovBySMul (G i) (K i) (A i) (B i)) :
CovBySMul ((i : ι) → G i) (∏ is, K i) ((↑s).pi A) ((↑s).pi B)
theorem CovByVAdd.pi {ι : Type u_4} {G : ιType u_5} {X : ιType u_6} {s : Finset ι} [(i : ι) → AddGroup (G i)] [(i : ι) → AddAction (G i) (X i)] {A B : (i : ι) → Set (X i)} {K : ι} (hAB : is, CovByVAdd (G i) (K i) (A i) (B i)) :
CovByVAdd ((i : ι) → G i) (∏ is, K i) ((↑s).pi A) ((↑s).pi B)
theorem CovBySMul.inter {G : Type u_2} [Group G] {A B C : Set G} {K L : } (hA : CovBySMul G K C A) (hB : CovBySMul G L C B) :
CovBySMul G (K * L) C (A⁻¹ * A (B⁻¹ * B))
theorem CovByVAdd.inter {G : Type u_2} [AddGroup G] {A B C : Set G} {K L : } (hA : CovByVAdd G K C A) (hB : CovByVAdd G L C B) :
CovByVAdd G (K * L) C ((-A + A) (-B + B))
theorem CovBySMul.iInter {G : Type u_2} [Group G] {B : Set G} {ι : Type u_4} {A : ιSet G} {s : Finset ι} {K : ι} (h : is, CovBySMul G (K i) B (A i)) :
CovBySMul G (∏ is, K i) B (⋂ is, (A i)⁻¹ * A i)

If B is covered by Kᵢ-many translates of each Aᵢ, then it is covered by ∏ᵢ Kᵢ-many translates of ⋂ᵢ Aᵢ⁻¹ * Aᵢ.

theorem covBySMul_mulOpposite_iff {G : Type u_2} [Group G] {A B : Set G} {K : } :

Covering B by K right translates of A is the same as covering B⁻¹ by K left translates of A⁻¹.