Quasicomplemented lattices
Quasi-implication algebras
A quasi-implication algebra is introduced as an algebraic counterpart of an implication reduct of propositional logic having non-involutory negation (e.g. intuitionistic logic). We show that every pseudocomplemented semilattice induces a quasi-implication algebra (but not conversely). On the other hand, a more general algebra, a so-called pseudocomplemented q-semilattice is introduced and a mutual correspondence between this algebra and a quasi-implication algebra is shown.
Quasivarieties of De Morgan algebras
Quasivarieties of pseudo-MV-algebras.
Quasivarieties of symmetric distributive lattices.