Equational bases for varieties of Ockham algebras.

We consider the variety O of Ockham algebras and its subvarieties of the form P _m,n ( m > n ≥0), sometimes with an additional condition. We use Priestley duality and a remarkable theorem of Urquhart to develop a simple method for determining the equational bases of the subvarieties. The axioms that we obtain have the same canonical form and involve few variables. We illustrate our method by the detailed study of the variety MS ₂ and some considerations about P _3,2. [ABSTRACT FROM AUTHOR]