“…By abuse of notation, we refer to the simplices by their labeling under the discrete Morse function (the fact that pairs in V f are given the same label should not cause confusion). For each of the pairs (9,9), (6,6), (3,3), (2, 2), (1, 1) ∈ V f , we have the corresponding values l 9 = 11, l 6 = 8, l 3 = 5, l 2 = 2, and l 1 = 1. The corresponding strong collapses under the indicated vertices are given by S f 9 = {(9, 9), (10, 10), (11,11)}, S Hence there is a single critical pair, namely, (13,13), so that scrit(f ) = {0, (13, 13)}.…”