%0 Journal Article %A A. M. Bikchentaev %T Differences of idempotents in $C^*$-algebras and the~quantum Hall effect %J Teoretičeskaâ i matematičeskaâ fizika %D 2018 %P 75-80 %V 195 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/TMF_2018_195_1_a6/ %G ru %F TMF_2018_195_1_a6