On the completion of a partial integral matrix to a unimodular matrix Original Research Article

We prove that if a partial integral matrix has a free diagonal then this matrix can be completed to a unimodular matrix. Such a condition is necessary in a general sense. Consequently if an n × n (n greater-or-equal, slanted 2) partial integral matrix has 2n − 3 prescribed entries and any n entries of these do not constitute a row or a column then it can be completed to a unimodular matrix. This improves a recent result of Zhan.