The necessary and sufficient conditions of similarity of two idempotent matrices are proved, the idempotency of linear combinations of two idempotent matrices is discussed.
The tripeptide Arginyl-Glycyl-Aspartic acid (RGD) is a common cell recognition site of many adhesive proteins contained in extracellular matrices and in the blood .
In the practical applications of highly nonnormal matrices, these theorems may be more useful than their generalized eigenvalue special cases and may provide more descriptive information.
One kind of inverse eigenvalue problems, whose solutions are required to be normal or diagonalizable matrices, is investigated in quaternionic quantum mechanics.
They are giant, inscrutable matrices of floating point numbers that we nudge in the direction of better performance until they inexplicably start working.