%0 Journal Article %A Tkachuk, Vladimir V. %T Some non-multiplicative properties are $l$-invariant %J Commentationes Mathematicae Universitatis Carolinae %D 1997 %P 169-175 %V 38 %N 1 %U http://geodesic.mathdoc.fr/item/CMUC_1997_38_1_a15/ %G en %F CMUC_1997_38_1_a15