%0 Journal Article %T Journal for the Cultivation of Mathematics. Abstracts %J Czechoslovak Mathematical Journal %D 1956 %P 563-579 %V 6 %N 4 %U http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1956.100221/ %R 10.21136/CMJ.1956.100221 %G en %F 10_21136_CMJ_1956_100221