  Let $ex(n, P)$ be the maximum possible number of ones in any 0-1 matrix of
dimensions $n \times n$ that avoids $P$. Matrix $P$ is called minimally
non-linear if $ex(n, P) = \omega(n)$ but $ex(n, P') = O(n)$ for every strict
subpattern $P'$ of $P$. We prove that the ratio between the length and width of
any minimally non-linear 0-1 matrix is at most $4$, and that a minimally
non-linear 0-1 matrix with $k$ rows has at most $5k-3$ ones. We also obtain an
upper bound on the number of minimally non-linear 0-1 matrices with $k$ rows.
  In addition, we prove corresponding bounds for minimally non-linear ordered
graphs. The minimal non-linearity that we investigate for ordered graphs is for
the extremal function $ex_{<}(n, G)$, which is the maximum possible number of
edges in any ordered graph on $n$ vertices with no ordered subgraph isomorphic
to $G$.
