Primitive normality and additivity of free projective and strongly flat polygons
We study into monoids S over which the axiomatizable class of all free, projective, or strongly flat S-polygons is primitive normal or additive. It is proved that an axiomatizable class of all free, projective, or strongly flat S-polygons is primitive normal iff a monoid S primitive normal. Also it is shown that an axiomatizable class of all free, projective, or strongly flat S-polygons is not additive for any monoid S.