  We consider bounds on maximum nullity of a graph via transversal numbers of
compatible collections of forts. Results include generalizations of theorems
from symmetric to combinatorially symmetric matrices, special bases of matrix
nullspaces derived from transversal sets, and examples of issues that arise
when considering only minimal forts and how to avoid them. We also show an
important difference between constructing symmetric and combinatorially
symmetric matrices associated to a graph whose nullspaces are supported on
collections of disjoint forts.
