The expression "\Gamma(x) \Gamma(y)" involves the Gamma function, a mathematical function that extends the concept of factorials to non-integer values. For positive integers, \Gamma(n) = (n-1)!, but it is defined for all complex numbers except the non-positive integers. This function is useful in various fields, including statistics and complex analysis. When multiplying two Gamma functions, \Gamma(x) \Gamma(y), it can be related to other mathematical concepts, such as the Beta function. The relationship between these functions often appears in probability theory and combinatorics, providing tools for solving integrals and evaluating probabilities in continuous distributions.