On some Properties of Quasi MV Algebras and √quasi-MV Algebras. Part III.

In the present paper, which is a sequel to [14] and [3], we investigate further the structure theory of quasi-MV algebras and √′quasi-MV algebras. In particular: we provide an improved version of the subdirect representation theorem for both varieties; we characterise the Ursini ideals of quasi-MV algebras; we establish a restricted version of J´onsson’s lemma, again for both varieties; we simplify the proof of standard completeness for the variety of √′ quasi-MV algebras; we show that this same variety has the finite embeddability property; finally, we investigate the structure of the lattice of subvarieties of √′quasi-MV algebras