Recall skeletal preorders and dagger preorders.
Show that a skeletal dagger preorder is just a discrete preorder (and hence can be identified with a set)
Because preorders are reflexive, we just have to show \(a \ne b \implies a \not\leq b\), or its contrapositive: \(a \leq b \implies a = b\).
\(a \leq b \overset{dagger}{\implies} b \leq a \overset{skeletal}{\implies} a = b\)