“…The reason is that for n ≤ 1, M(N h,n ) and T (N h,n ) have particularly simple generators. We emphasise, however, that finite generating sets for these groups are known for arbitrary n [15,16]. It is worth mentioning at this point, that the first finite generating set for M(N h,0 ), h ≥ 3, was obtained by Chillingworth [3] using Lickorish's results [8,9].…”