Take the smallest cellular structure forthe circle X =S1 consisting
of a single 0-cell and a single 1-cell. Let Y be the same circlewith two 0-cells and two
1-cells with the ends attached to the two different 0-cells. Count(in particular, describe)
all possible (up to homotopy) cellular maps X ? Y and Y ? X
question related to Topological data analysis 2
