TY - JOUR AU - Constantinos N. Yatras TI - Characteristic of M-polysymmetrical Hyperrings and some properties of M-Polysymmetrical Hyperrings with Unity JO - Δελτίο της Ελληνικής Μαθηματικής Εταιρίας PY - 1996 SP - 115 EP - 125 VL - 38 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/DEME_1996__38_a20/ LA - gr ID - DEME_1996__38_a20 ER -