Let $S$ be a Noetherian scheme and $X,Y$ be $S$-schemes of finite type. Consider the functor $X^Y$ given by $T \mapsto Mor_S(Y \times_S T,X)$. When is this functor representable by an $S$-scheme of finite type?
Is it true when $Y \rightarrow S$ is finite and flat?
In http://www.math.harvard.edu/~gaitsgde/grad_2009/SeminarNotes/Sept17(Bun(G)).pdf (Thm 1.6) it is shown that $X^Y$ is representable if $X \rightarrow S$ is quasi-projective and $Y \rightarrow S$ is projective. Dennis Gaitsgory explained to us that this implies that $X^Y$ is representable by a locally finite type scheme.