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In mathematics, a matrix polynomial is a polynomial with matrices as variables. Given an ordinary, scalar-valued polynomial : this polynomial evaluated at a matrix ''A'' is : where ''I'' is the identity matrix. A matrix polynomial equation is an equality between two matrix polynomials, which holds for the specific matrices in question. A matrix polynomial identity is a matrix polynomial equation which holds for all matrices ''A'' in a specified matrix ring ''Mn''(''R''). == Characteristic and minimal polynomial == The characteristic polynomial of a matrix ''A'' is a scalar-valued polynomial, defined by . The Cayley–Hamilton theorem states that if this polynomial is viewed as a matrix polynomial and evaluated at the matrix ''A'' itself, the result is the zero matrix: . The characteristic polynomial is thus a polynomial which annihilates ''A''. There is a unique monic polynomial of minimal degree which annihilates ''A''; this polynomial is the minimal polynomial. Any polynomial which annihilates ''A'' (such as the characteristic polynomial) is a multiple of the minimal polynomial. It follows that that given two polynomials ''P'' and ''Q'', we have if and only if : where denotes the ''j''th derivative of ''P'' and are the eigenvalues of ''A'' with corresponding indices (the index of an eigenvalue is the size of its largest Jordan block). 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Matrix polynomial」の詳細全文を読む スポンサード リンク
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