Q2 (10 points) Let g : X - Y, f : Y - Z. (a) Prove that if f . g : X - Z is invertible then: (i) f must be surjective. (ii) g must be injective. (b) Find functions f, g (and sets X, Y, Z ) which demonstrate that f . g can be invertible, even if f is not injective and g is not surjective. + Drag and drop an image or PDF file or click to browse