2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/59430It is shown that any finite, rank-connected, dismantlable lattice is lexicographically shellable (hence Cohen-Macaulay). A ranked, interval-connected lattice is shown to be rank-connected, but a rank-connected lattice need not be interval-connected. An example of a planar, rank-connected lattice that is not admissible is given.5 pagesCombinatorics06A; 05Atext