The meaning of Sigma in statistical analysis is a function of whether you use the upper or lower case of the letter. The uppercase use of sigma denotes a summation while the lowercase represents a ...

Trigonometric sums and summation formulas have long served as essential tools for elucidating periodic phenomena across mathematics and the physical sciences.

Walter Strodt, Remarks on the Euler-Maclaurin and Boole Summation Formulas, The American Mathematical Monthly, Vol. 67, No. 5 (May, 1960), pp. 452-454 ...

92.43 Euler's little summation formula and special values of the zeta function THOMAS J. OSLER The Mathematical Gazette , pp. 295-299 (5 pages) ...