CONSTRUCTIVE COUNTERPARTS OF A QUASIORDER

MARIAN BARONI

“Dunărea de Jos” University of Galați, Str. Domnească 111, Galați 800201, ROMANIA e-mail: marian.baroni@ugal.ro

Abstract

Co-quasiorder relations, the constructive counterpart of classical quasiorder relations are examined within the framework of Bishop’s constructive mathematics. Two classically equivalent, but constructively inequivalent, notions of co-quasorder are investigated. It turns out that a weak co-quasorder is a co-quasiorder if and only if it is quasi-detachable. As a consequence, the incomparability relation associated to a co-quasiorder is quasi-detachable.

Keywords

constructive mathematics co-quasiorder weak co-quasiorder quasi-detachability order incomparability