Definition:Proper Morphism of Schemes

Definition
Let $\struct {X, \OO_X}$ and $\struct {Y, \OO_Y}$ be schemes.

Let $f : \struct {X, \OO_X} \to \struct {Y, \OO_Y}$ be a morphism of schemes.

$f$ is proper $f$ is separated, of finite type and universally closed.