On determinant zeros of boolean matrices

The properties of exteriority and interiority of square matrices with elements from arbitrary Boolean algebra are studied in this paper. The exterior and interior parts form a degenerate part of a matrix with zero determinant. It is shown, in particular, that the set of exterior parts is a normal set in the Boolean algebra of all Boolean square matrices and it is a lower semilattice. The set of interior parts is an upper semilattice. Moreover linear combinations and even polynomials of the interiorities also belong to it.