%0 Journal Article %T Theses Abstracts %J Canadian mathematical bulletin %D 1969 %P 701-703 %V 12 %N 5 %U http://geodesic.mathdoc.fr/articles/10.1017/S0008439500030952/ %R 10.1017/S0008439500030952 %F 10_1017_S0008439500030952