The 
-skeleton of a simplicial
complex 
, where 
is a nonnegative integer,
is the simplicial subcomplex consisting
of all simplices of 
of dimension at most 
, denoted 
(Munkres 1993).
For a CW-complex 
,
the 
-skeleton 
is the union of its cells of dimension at most 
.
The special case 
is the 1-skeleton (Hatcher 2002).
