matrices.md

matrix construction external matrix M_E (16×16) circulant of 4×4 MDS sub-blocks, following Poseidon2 paper §4.2. 4×4 sub-block M4 circulant — each row is the previous row rotated right by one position. full 16×16 construction the state is partitioned into four 4-element chunks. M4 is applied to…