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In mathematics, a Cauchy matrix, named after Augustin Louis Cauchy, is an ''m''×''n'' matrix with elements ''a''''ij'' in the form : where and are elements of a field , and and are injective sequences (they do not contain repeated elements; elements are ''distinct''). The Hilbert matrix is a special case of the Cauchy matrix, where : Every submatrix of a Cauchy matrix is itself a Cauchy matrix. == Cauchy determinants == The determinant of a Cauchy matrix is clearly a rational fraction in the parameters and . If the sequences were not injective, the determinant would vanish, and tends to infinity if some tends to . A subset of its zeros and poles are thus known. The fact is that there are no more zeros and poles: The determinant of a square Cauchy matrix A is known as a Cauchy determinant and can be given explicitly as : (Schechter 1959, eqn 4). It is always nonzero, and thus all square Cauchy matrices are invertible. The inverse A−1 = B = () is given by : (Schechter 1959, Theorem 1) where ''A''i(x) and ''B''i(x) are the Lagrange polynomials for and , respectively. That is, : with : 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「Cauchy matrix」の詳細全文を読む スポンサード リンク
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