%0 Journal Article %A Marc P. Thomas %T The canonical test case for the non-commutative Singer–Wermer conjecture %J Studia Mathematica %D 2009 %P 43-63 %V 194 %N 1 %U http://geodesic.mathdoc.fr/articles/10.4064/sm194-1-3/ %R 10.4064/sm194-1-3 %G en %F 10_4064_sm194_1_3