Imagine we have two lens, one convex and one concave, spaced in such a way that the convex lens is before the concave lens. Now each lens has its own focus length and both are spaced such that the concave lens focus is to the right of the convex's. Furthermore, imagine that an arrow with a real length (in the $+y$-direction) is placed at the focus of the convex lens.
It seems that the rays that are incident on the convex lens will be redirected so as to emerge parallel to the optical axis. The image will then appear to be coming from infinite to the concave lens. Now these rays, once going through the concave lens, will diverge with the rays appearing to come from the concave lens focal point.
The question is: what is the magnification of the arrow by the optical system? In other words, can the arrow have a magnification and if so, how?