Packing of (0, 1)-matrices
The MATRIX PACKING DOWN problem asks to find a row permutation of a given -matrix in such a way that the total sum of the first non-zero column indexes is maximized. We study the computational complexity of this problem. We prove that the MATRIX PACKING DOWN problem is -complete even when restricted to zero trace symmetric -matrices or to -matrices with at most two 's per column. Also, as intermediate results, we introduce several new simple graph layout problems which are proved to be...