In this note we characterize the one-generated subdirectly irreducible MV-algebras and use this characterization to prove that a quasivariety of MV-algebras has the relative congruence extension property if and only if it is a variety.
The investigation of orthocomplemented lattices with a symmetric difference initiated the following question: Which orthomodular lattice can be embedded in an orthomodular lattice that allows for a symmetric difference? In this paper we present a necessary condition for such an embedding to exist. The condition is expressed in terms of -valued states and enables one, as a consequence, to clarify the situation in the important case of the lattice of projections in a Hilbert space.
On se propose de donner une interprétation algébrique (en calcul des propositions classiques) des notions d'arbres, d'ensembles de Hintikka, de la méthode des tableaux de Beth-Hintikka Smullyan.
We set up axioms characterizing logical connective implication in a logic derived by an ortholattice. It is a natural generalization of an orthoimplication algebra given by J. C. Abbott for a logic derived by an orthomodular lattice.