  Curiously, while the logic  \(\mathsf{S4LP}\) seems quite natural, a Realization Theorem  has been problematic for it: no such theorem can be proved if one  insists on what are called normal realizations (Kuznets  2010). Realization of implicit knowledge modalities in  \(\mathsf{S4LP}\) by explicit  justifications which would respect the epistemic structure remains a  major challenge in this area.