Positive-definite function: Difference between revisions

Revision as of 11:46, 3 February 2022

Revision as of 08:05, 5 February 2022

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\ge 0,

</math>

where <math>\tilde{A}^{(f)} = \big( f(\phi(x_i) - \phi(x_j)) = f(\tilde{x}_i - \tilde{x}_j) \big)_{i, j}</math> where <math>\tilde{x}_k := \phi(x_k)</math> are distinct as <math>\phi</math> is [[linear]].<ref>{{cite book |last1=Cheney |first1=Elliot Ward |title=A course in Approximation Theory |date=2009 |publisher=American Mathematical Society |isbn=9780821847985 |pages=77-7877–78 |url=https://books.google.decom/books/about/A_Course_in_Approximation_Theory.html?id=II6DAwAAQBAJ&redir_esc=y |access-date=3 February 2022}}</ref>

===Bochner's theorem===