!!! Overview
[{$pagename}] (or sometimes ambiguously called a unit matrix), of size n is the n × n square [matrix] with ones on the main diagonal and zeros elsewhere and is often denoted by In, or simply by I.

[Identity matrix/identity-matrix.png]

The [{$pagename}] itself is invertible, being its own inverse

The [{$pagename}] of a given size is the only [idempotent] [matrix] of that size having full rank. That is, [{$pagename}] is the only [matrix] such that:
* when multiplied by itself the result is itself
* all of its rows, and all of its columns, are [linearly independent].

The principal square root of an [{$pagename}] is itself, and this is its only positive definite square root. Every [{$pagename}] with at least two rows and columns has an infinitude of symmetric square roots.



!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]