This problems has Hartshorne Height 1.
- The key to this problem is to reduce statements of morphisms of sheaves to statements about elements of sheaf groups.
- Defining the sum of two morphisms is just defined pointwise on every open set as you would expect.
- In particular, the zero and gluing sheaf axioms for Hom (here the underline means sheaf Hom) only require that G be a sheaf. For example, for the zero axiom, if a morphism restricts to 0 on some open cover means that the original morhpism maps elements to other elements that restricts to 0 in the groups of G, as G is a sheaf, the morphism must be mapping everything to 0.