fact: CoInductive simulates {E : Type -> Type} {R : Type} : itree E R -> itree E R -> Prop := | SimStep : forall t1 t2, (forall ev t1', step ev t1 t1' -> exists t2', step ev t2 t2' /\ simulates t1' t2') -> simulates t1 t2.
imports: Paco(paco) ITree(Basics.Utils Axioms Core.ITreeDefinition Eq.Eqit Eq.UpToTaus Eq.SimUpToTaus Eq.Shallow Eq.Paco2)