Associated 3-Designs

HadamardRowDesign(H, i) : AlgMatElt, RngIntElt -> Dsgn
Given an n x n Hadamard matrix H (with n ≥4) and an integer i with 1 ≤i ≤n, returns the Hadamard 3--design corresponding to the ith row of H.
HadamardColumnDesign(H, i) : AlgMatElt, RngIntElt -> Dsgn
Given an n x n Hadamard matrix H (with n ≥4) and an integer i with 1 ≤i ≤n, returns the Hadamard 3--design corresponding to the ith column of H.

Example Hadamard_hadamard-designs (H157E2)

There is only one Hadamard equivalence class of 8 x 8 Hadamard matrices. We construct one matrix, and two of its designs.
> R := MatrixRing(Integers(), 8);
> H := R![1,  1,  1,  1,  1,  1,  1,  1,
>         1,  1,  1,  1, -1, -1, -1, -1,
>         1,  1, -1, -1,  1,  1, -1, -1,
>         1,  1, -1, -1, -1, -1,  1,  1,
>         1, -1,  1, -1,  1, -1, -1,  1,
>         1, -1,  1, -1, -1,  1,  1, -1,
>         1, -1, -1,  1, -1,  1, -1,  1,
>         1, -1, -1,  1,  1, -1,  1, -1];
> IsHadamard(H);
true
> DR := HadamardRowDesign(H, 3);
> DR: Maximal;
3-(8, 4, 1) Design with 14 blocks
Points: {@ 1, 2, 3, 4, 5, 6, 7, 8 @}
Blocks:
    {1, 2, 5, 6},
    {1, 2, 7, 8},
    {1, 2, 3, 4},
    {1, 4, 5, 7},
    {1, 4, 6, 8},
    {1, 3, 6, 7},
    {1, 3, 5, 8},
    {3, 4, 7, 8},
    {3, 4, 5, 6},
    {5, 6, 7, 8},
    {2, 3, 6, 8},
    {2, 3, 5, 7},
    {2, 4, 5, 8},
    {2, 4, 6, 7}
> HadamardColumnDesign(H, 8);
3-(8, 4, 1) Design with 14 blocks
V2.28, 13 July 2023