The inclusion map of a subset 
into a set 
is the injection 
defined by 
for all 
.
Inclusion Map
See also
Long Exact Sequence of a Pair AxiomExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Inclusion Map." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/InclusionMap.html