Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4659046 | Topology and its Applications | 2013 | 11 Pages |
Suppose that for each i⩾0, Xi is a Hausdorff continuum, and fi+1:Xi+1→2Xi is an upper semicontinuous function with a connected graph Gi+1, such that πi(Gi+1)=Xi and πi+1(Gi+1)=Xi+1 (πi and πi+1 denote the respective projections of Gi+1 to Xi and Xi+1). We give a condition on the graphs called an HC-sequence, and show that {fi:i>0} admits an HC-sequence if and only if there exists a connected basic open set U=∏0⩽i