... unimodular

An integer square matrix $A$ of is unimodular if $\det A = \pm 1$ . A matrix $B$ is totally unimodular if every non-singular square submatrix of $B$ is unimodular.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.