Positive definite functions, completely monotone functions, the Bernstein-Widder theorem, and Schoenberg’s theorem
نویسنده
چکیده
So, 〈(A ∗B)ei, ej〉 = 〈Aei, ej〉 〈Bei, ej〉 . The Schur product theorem states that if A,B ∈ L (C) are positive then their Hadamard product A ∗B is positive. 1John B. Conway, A Course in Functional Analysis, second ed., p. 33, Proposition 2.12. 2John B. Conway, A Course in Functional Analysis, second ed., p. 34, Proposition 2.13. 3Ward Cheney and Will Light, A Course in Approximation Theory, p. 81, chapter 12.
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