TY - JOUR AU - Derek Kitson TI - Ascent and descent for sets of operators JO - Studia Mathematica PY - 2009 SP - 151 EP - 161 VL - 191 IS - 2 UR - http://geodesic.mathdoc.fr/articles/10.4064/sm191-2-3/ DO - 10.4064/sm191-2-3 LA - en ID - 10_4064_sm191_2_3 ER -