Positive Definite Sequence

A sequence  is positive definite if the moment of every nonnegative polynomial which is not identically zero is greater than zero (Widder 1941, p. 132). Here, the moment of a polynomial

with respect to the sequence  is defined as

(Widder 1941, p. 102).

REFERENCES:

Widder, D. V. The Laplace Transform. Princeton, NJ: Princeton University Press, 1941.