Lemma 106.8.5. Let $f : \mathcal{X} \to \mathcal{Y}$ be a morphism of algebraic stacks which is representable by algebraic spaces. Then the following are equivalent
$f$ is formally smooth,
for every scheme $T$ and morphism $T \to \mathcal{Y}$ the morphism $\mathcal{X} \times _\mathcal {Y} T \to T$ is formally smooth as a morphism of algebraic spaces.
Comments (0)