clopen.solutions

Open problems

980 registered problems.

OP-00032 Open
The Hadamard conjecture
CO · combinatorial designs · Hadamard matrices · Randomstrasse101
OP-00056 Solved
The discrepancy of the Sylvester–Hadamard matrices H_k for odd k
CO · Boolean functions · discrepancy theory · Hadamard matrices · Randomstrasse101
OP-00076 Lean verified
Counting real Hadamard matrices
CO · Hadamard matrices · OpenProblemsInNLA · sign matrices
OP-00149 Partially resolved
A condition number of two for a sign matrix in every dimension
CO · approximate Hadamard matrices · condition numbers · OpenProblemsInNLA · sign matrices
OP-00150 Partially resolved
The optimal decay exponent for the conditioning of sign matrices
CO · approximate Hadamard matrices · condition numbers · OpenProblemsInNLA · sign matrices
OP-00188 Open
Cryer's Hadamard complete-pivoting conjecture
NA · Gaussian elimination · growth factors · Hadamard matrices · OpenProblemsInNLA
OP-00699 Solution claimed
The maximum number of mutually unbiased bases in dimension six
CO · AIM Open Applied Problems · complex Hadamard matrices · mutually unbiased bases