I would like to know what is a idempotent matrix? Also, which invertible matrices are also idempotent and can a matrix be nilpotent and idempotent at the same time?
What is a idempotent matrix?
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linear-algebra
matrices
1 Answers
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In algebra, an idempotent matrix is a matrix which, when multiplied by itself, yields itself. (guess where this is from...)
With the exception of the identity matrix, an idempotent matrix is singular...
Does the zero matrix count?
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3In fact, there are exactly three kinds of idempotant matrices: the unit matrix (invertible), the zero matrix (nilpotent) and all others (neither). – 2012-10-09