Hallo,
I have the following question. Let $f:X\rightarrow Y$ be a morphism of stacks. Assume I know that $Y$ is representable by an algebraic scheme and that for every scheme $T$ and $\xi\in Y(T)$ the fiber $X\times_{f,\xi}T$ is representable by an algebraic scheme.
Is it true that also $X$ is representable by an algebraic scheme?
Thanks
