Lean4
/-- Simplify an expression in `Cat` using basic properties of `NatTrans.app`. -/
def catAppSimp (e : Expr) : MetaM Simp.Result :=
simpOnlyNames
[``Cat.comp_obj, ``Cat.whiskerLeft_app, ``Cat.whiskerRight_app, ``Cat.id_app, ``Cat.comp_app, ``Cat.eqToHom_app,
``Cat.leftUnitor_hom_app, ``Cat.leftUnitor_inv_app, ``Cat.rightUnitor_hom_app, ``Cat.rightUnitor_inv_app,
``Cat.associator_hom_app, ``Cat.associator_inv_app, ``eqToHom_refl, ``Category.comp_id, ``Category.id_comp]
e (config := { decide := false })