20 Answers votes newest views recent 20Hard Cube Puzzle 11Signatures on the infinite symmetric group 11Non-split extensions of $GL_n(F_q)$ by $F_q^n$ ? 11How many finite simple groups of order $p+1$? 11Irreducible representation flipping two elements 10Is there any way to check whether a group is residually solvable? 10Integers in a triangle, and differences 8Why are this operator’s primes the Sophie Germain primes? 8Does any research mathematics involve solving functional equations? 5Can a problem be simultaneously polynomial time and undecidable? 5More open problems 4A set for which it is hard to determine whether or not it is countable. 4Superfluous definitions 3How many elements does it take to normally generate a group? 3does this group have a name? 2Isomorphism of semidirect products 2Semi-simple matrices over fields of finite characteristic 2Sphere packing in a sphere 1Rank of sum of Galois conjugates of a matrix 0Can the I-fold direct product be free?