Suppose $U$ and $V$ are vector spaces and define a function $\ltdefn{Z}{U}{V}$ by $\lt{T}{\vect{u}}=\zerovector_{V}$ for every $\vect{u}\in U$. Then Exercise IVLT.M60 asks you to formulate the theorem: $Z$ is invertible if and only if $U=\set{\zerovector_U}$ and $V=\set{\zerovector_V}$. What would a matrix representation of $Z$ look like in this case? How does Theorem IMR read in this case?