  Let G be a graph with undirected and directed edges. Its representation is
given by assigning a vector space to each vertex, a bilinear form on the
corresponding vector spaces to each directed edge, and a linear map to each
directed edge. Two representations A and A' of G are called isomorphic if there
is a system of linear bijections between the vector spaces corresponding to the
same vertices that transforms A to A'. We prove that if two representations are
isomorphic and close to each other, then their isomorphism can be chosen close
to the identity.
