A binary matrix is a matrix with entries from the set {0, 1}. We say that a binary matrix A contains a binary matrix S if S can be obtained from A by removal of some rows, some columns, and changing some 1-entries to 0-entries. If A does not contain S, we say that A avoids S. A k-permutation matrix P is a binary k× k matrix with exactly one 1-entry in every row and one 1-entry in every column. ...