“…The group GLnB/E,(A, B) = K1 (A, B) = GLI B/W(A, B) is also an abelian group which does not depend on n for n >_ 2, where W(A, B) is the subgroup of GLl A generated by the elements of the form (a + c + abc) (a + c + cba) -1 with a E B, b E A, c E 1 + B (see [17], [22]) . So the group G,(A, B)/E(A, B), which classifies all subgroups H of GL,,A normalized by EnA and with the same "leveF B, is two-step nilpotent .…”