  The minimum rank of a simple graph $G$ is defined to be the smallest possible
rank over all symmetric real matrices whose $ij$th entry (for $i\neq j$) is
nonzero whenever $\{i,j\}$ is an edge in $G$ and is zero otherwise. Minimum
rank is a difficult parameter to compute. However, there are now a number of
known reduction techniques and bounds that can be programmed on a computer; we
have developed a program using the open-source mathematics software Sage to
implement several techniques. In this note, we provide the source code for this
program.

Combinatorics