Local functions named for this letter defined for finite field curves are generalized by the Weil (“vay”) conjectures. The norms of algebraic number fields define functions named for this letter and Richard Dedekind (“DAY-duh-kind”). Euler’s (“OY-lur’s”) solution to the Basel (“BAH-zel”) problem inspired one mathematician to define a function named for (10[1])this letter, (10[1])which is equal to “pi (10[1])squared over six” at two. Evaluating a function named for this letter (10[1])at “s equals 1” (10[2])produces the harmonic series. The roots of a (-5[1])function named for this letter would provide a strong asymptotic bound on the distribution of prime numbers. It is conjectured that the zeros of a function named for this letter are either negative even integers or have real part one half. For 10 points, name this Greek letter that denotes a function named for Bernhard Riemann. ■END■ (10[2])