Residue and injectivity of disjoint affine cubes #
At each coordinate all sums collapse to at most one direction. Summing those
coordinate identities makes the full Hamming residue affine over ZMod 3 in the
zero/one interpretations of the cube parameters.
theorem
Algebraic.BooleanCube.ModThree.Internal.cubeLinearMap_coordinate
{ι : Type u_1}
{J : Type u_2}
[Fintype J]
(v : J → ι → ZMod 2)
(disjoint : DisjointDirections v)
(z : J → ZMod 2)
(j : J)
(i : ι)
(nonzero : v j i ≠ 0)
:
A coordinate touched by a direction reads only that cube parameter.
theorem
Algebraic.BooleanCube.ModThree.Internal.affineCube_injective
{ι : Type u_1}
{J : Type u_2}
[Fintype J]
(a : ι → ZMod 2)
(v : J → ι → ZMod 2)
(disjoint : DisjointDirections v)
(nonzero : ∀ (j : J), v j ≠ 0)
:
Function.Injective (affineCube a v)
Disjoint nonzero directions give an injective affine cube.
theorem
Algebraic.BooleanCube.ModThree.Internal.residue_affineCube
{ι : Type u_1}
{J : Type u_2}
[Fintype ι]
[Fintype J]
(a : ι → ZMod 2)
(v : J → ι → ZMod 2)
(disjoint : DisjointDirections v)
(z : J → ZMod 2)
:
Full Hamming residue restricts to a signed affine sum on a disjoint cube.