Abstract:
Let X be a connected paracompact Hausdorff space, freely acted on by a cyclic group of prime order p with generator T. Let f:X→M be a continuous mapping of X into a topological manifold M of dimension m. Put A(f)={x∈X∣f(x)=f(Tx)=⋯=f(Tp−1x)}. If M is orientable over Zp, ˇHi(X;Zp)=0 for 0<i<n, and f∗:ˇHm(M;Zp)→ˇHm(X;Zp) has zero image, then, for X weakly locally contractible, dimA(f)⩾n−m(p−1). If, in addition, X is an N-dimensional topological manifold,
then dimA(f)⩾N−m(p−1). For p=2, suppose ˇH∗(X;Z2)=H∗(Sn;Z2) and dimX∞, while M is a connected compact closed manifold of dimension n with a free involution T′. Let A′(f)={x∈X∣f(Tx)=T′f(x)}, and suppose f∗:ˇHn(M;Z2)→Hn(X;Z2) is
a monomorphism. Then A′(f)≠∅.
Bibliography: 5 titles.