Chowla’s cosine problem
Epoch AIStudy how small the negative minimum of a cosine sum can be relative to the number of its distinct positive frequencies.
Study how small the negative minimum of a cosine sum can be relative to the number of its distinct positive frequencies.
Find imaginary quadratic fields with large odd-prime class-group ranks, and develop constructions and exact verification methods.
Find seven distinct nonzero rational numbers whose pairwise products plus one are rational squares, or prove none exist.
Determine whether every biplanar graph can be colored with nine colors, or construct a graph that requires at least ten.
Construct a shape that admits at least seven surrounding layers of congruent copies but cannot tile the entire plane.
Prove or disprove that every rational Hodge class on a smooth complex projective variety is a rational linear combination of algebraic cycle classes.
Construct large point sets on integer grids with no three points on a line, or prove the proposed density impossible.
Prove or disprove that every nontrivial zero of the Riemann zeta function has real part one half.