Inclusion map

In mathematics, if ${\displaystyle A}$ is a subset of ${\displaystyle B}$, then the inclusion map (also inclusion function, insertion, or canonical injection) is the function ${\displaystyle \iota }$ that sends each element, ${\displaystyle x}$, of ${\displaystyle A}$ to ${\displaystyle x}$, treated as an element of ${\displaystyle B}$:

...
Wikipedia