2 problems

Let $\mathcal{A}$ be an abelian category with enough injectives, and let $A\in\mathcal{A}$. Consider the contravariant functor $\operatorname{Ext}_{\mathcal{A}}^{1}(-,A)$. Auslande…

Let $\mathcal{A}$ be an abelian category with enough projectives, and let $A\in\mathcal{A}$. Consider the covariant functor $\operatorname{Ext}_{\mathcal{A}}^{1}(A,-)$. Dual Auslan…