| Letφ:(Z2)k×Mn→Mn denote a smooth action of the group (Z2)k={T1,T2,…,Tk| Ti2=1,TiTj=TjTi} on a closed manifold Mn.The fixed point set F of the action is thedisjoin union of closed submanifolds of Mn,which are finite in number.If each componentof F is of constant dimension n - r, we say that F is of constant codimension r. Let MOn denote the unoriented cobordism group of dimension n and Jn,kr the set of n dimensional unoriented cobordism class of Mn that admits a (Z2)k-action with fixed point set of constant codimension r.Jn,kr is asubgroup of MOn and J*,kr=∑n≥rJn,kr is an ideal of the unoriented cobordism ring MO* =∑n≥0MOn.In this paper, we determine J*,k2k+11 by constructing indecomposable manifolds M and defining appropriate (Z2)k-action on M such that the fixed point set of actionis of constant codimension 2k+11. |