 The interested reader can examine Blok &amp; Rebagliato 2003 for a study devoted to algebraic semantics of logics and Moraschini forthcoming for the most recent results on the topic (in this paper there is a proof of the fact that the natural class of algebras of the local normal modal logic \(\blK\), namely the class of modal algebras, is not an algebraic semantics (for any set of equations) for it).