Simplicial complexes Posets ESPACIOS TOPOLOGICOS FINITOS FINITE TOPOLOGICAL SPACES Finite topological spaces CW-complexes Collapses Combinatorial manifolds Finite spaces 2-CATEGORIAS 2-CATEGORIES ALEXANDER DER DUALITY ALEXANDER DUALS ANDREWS-CURTIS CONJECTURE ASFERICIDAD ASPHERICITY CELLULAR COMPLEXES CLASIFICACION DE GRUPOS SIMPLES CLASSIFICATION OF FINITE SIMPLE GROUPS CLASSIFYING SPACES COMBINATORIAL MANIFOLDS COMPLEJOS CELULARES COMPLEJOS LOT COMPLEJOS SIMPLICIALES CONJETURA DE ANDREWS-CURTIS CONJETURA DE QUILLEN CW-COMPLEJOS CW-COMPLEXES Cellular homology DUAL DE ALEXANDER