Before revision:  The empirical relation, h_{xy}\le [ h_{xx + h_{yy ]/2 was confirmedjust for q>0 , while for q<0 there was a deviation from this relation .
After revision:  The empirical relation, h_{xy}\le [ h_{xx + h_{yy ]/2 , is confirmed. Mentioned relation for q>0 , while for q<0 there was a deviation from this relation .