1. The problem statement, all variables and given/known data Let V be a finite-dimensional vector over ℝ, and let S and T be linear transformations from V to V Show that n(ST)≤n(S)+n(T) Given Hints Consider the restriction of S to W where W=im(T) Can someone please tell me what the above hint means? I haven't attempted a solution, but then I'm not asking for a hint for the solution. I just require the definition of a restriction please! I haven't been able to find a definition of one in my lecture notes. They are just mentioned. Thanks!