# Difference between revisions of "Identity matrix"

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− | In [[matrix algebra]], the '''identity matrix''' is a [[square matrix]] which has all the entries on the main [[diagonal]] equal to one and all the other, off-diagonal, entries equal to zero. The identity matrix acts as the [[identity element]] for [[matrix multiplication]]. | + | In [[matrix algebra]], the '''identity matrix''' is a [[square matrix]] which has all the entries on the main [[diagonal]] equal to one and all the other, off-diagonal, entries equal to zero. The identity matrix acts as the [[identity element]] for [[matrix multiplication]]. Its entries are those of the [[Kronecker delta]]. |

## Revision as of 19:44, 8 December 2008

In matrix algebra, the **identity matrix** is a square matrix which has all the entries on the main diagonal equal to one and all the other, off-diagonal, entries equal to zero. The identity matrix acts as the identity element for matrix multiplication. Its entries are those of the Kronecker delta.