Etymology

Today it means: An identity for a sequence of orthogonal polynomials: ∑ⱼ₌₀ⁿ(f_j(x)f_j(y))/(h_j)=(k_n)/(h_nk_n+1)(f_n(y)f_n+1(x)-f_n+1(y)f_n(x))/(x-y) where fⱼ(x) is the jth term of a set of orthogonal polynomials of squared norm hⱼ and leading coefficient kⱼ. Full definition →