An induced subcomplex of a simplicial complex on a subset
of its vertices
is the subcomplex consisting of all simplices of
whose vertices
belong to
.
It is also called the full subcomplex on
and is denoted
.
For example, three vertices of a simplicial complex induce a filled triangle precisely when that triangle is a simplex of the original complex. If only its three edges are present, the induced subcomplex is a circle. An induced subcomplex therefore records higher-dimensional faces as well as the induced subgraph of the edge graph.
The inclusion maps of induced subcomplexes are used to define a tight triangulation.