Cumulants in Noncommutative Probability Theory I. Noncommutative Exchangeability Systems
نویسنده
چکیده
Cumulants linearize convolution of measures. We use a formula of Good to define noncommutative cumulants in a very general setting. It turns out that the essential property needed is exchangeability of random variables. Roughly speaking the formula says that cumulants are moments of a certain “discrete Fourier transform” of a random variable. This provides a simple unified method to understand the known examples of cumulants, like classical, free and various q-cumulants.
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