This is probably obvious to someone familiar with Category Theory (I'm just starting) but why are the following two statements true?
$$ \operatorname{Hom}(\operatorname{F}(S),-)\cong \operatorname{Map}(S,-)\cong \operatorname{Prod}(-;S) $$ and $$ \operatorname{Hom}(\operatorname{Copr}(\mathbb{Z};S),-)\cong \operatorname{Prod}(\operatorname{Hom}(\mathbb{Z},-);S) \cong \operatorname{Prod}(-;S), $$ Where, $\operatorname{F}(S)$ is the free abelian group on the set $S$, $\operatorname{Map}$ denotes morphisms in the category of sets, $\operatorname{Copr}(\mathbb{Z};S)$ is the coproduct of the family of copies of the integers $\mathbb{Z}$ indexed by the set $S$ and $\operatorname{Prod}$ is the product functor.
For the first 2 isomorphisms: The first one is the definition of the free Abelian group. For the second, take an Abelian group $A$. Consider the homomorphism $$f_A:Map(S,A) \to Prod(A;S): u \mapsto (u(s))_{s \in S}$$ and show that is an isomorphism.
The other isomorphisms are proved similarly.