Identity map

Definition

The "identity map", written on this project as $\text{Id}$, is a map which maps every item (in the domain) to itself, that is if $\text{Id}:X\rightarrow X$ is a function / map on some set $X$, then:

• $\forall x\in X[\text{Id}(x)\eq x]$

Conventions

If we are dealing with two sets $X$ and $Y$, then technically we must use differing notation for the identity map on each, for example $\text{Id}_X$ and $\text{Id}_Y$ however this is rarely needed and we (even I, Alec) usually just write $\text{Id}$ for both

Other notations

Sometimes $I$ is used for the identity map.

References

Grade: D

This page requires references, it is on a to-do list for being expanded with them.

Please note that this does not mean the content is unreliable, it just means that the author of the page doesn't have a book to hand, or remember the book to find it, which would have been a suitable reference.
The message provided is:

Not really important Alec (talk) 15:04, 15 December 2017 (UTC)