Laminated lattice Λ₉

T. W. Chaundy, The arithmetic minima of positive quadratic forms (I), Quart. J. Math. Oxford Ser. 17 (1946), 166–192, doi:10.1093/qmath/os-17.1.166.

This packing consists of a lattice in 9 dimensions. A Gram matrix for the lattice is given below as comma-separated values. See the table of densities for how this packing compares with other dimensions.

9 × 9 Gram matrix

4,2,-2,2,2,2,2,2,2
2,4,-2,2,2,2,2,2,2
-2,-2,4,0,0,-2,-2,-2,0
2,2,0,4,2,2,0,0,2
2,2,0,2,4,2,0,0,2
2,2,-2,2,2,4,0,0,1
2,2,-2,0,0,0,4,2,1
2,2,-2,0,0,0,2,4,1
2,2,0,2,2,1,1,1,4