2. The intersection of any two simplices of is a face of each of them
(Munkres 1993, p. 7).
Objects in the space made up of only the simplices in the triangulation of the space are called simplicial subcomplexes. When
only simplicial complexes and simplicial subcomplexes
are considered, defining homology is particularly easy
(and, in fact, combinatorial because of its finite/counting
nature). This kind of homology is called simplicial
homology.