Factorizations in the rings of the block matrices

The factorizations in the rings of the block triangular and the block diagonal matrices over an integral domain of finitely generated principal ideals are described. Conditions for existence and uniqueness up to the association of the factorizations in such rings are established. The construction of the factorizations of matrices is reduced to the factorizations of diagonal blocks of the block triangular matrices and the solving of the linear Sylvester matrix equations.