All Questions

For any integers $i$ and $j$ such as $1\le i<j\le6$, let $x_{ij}$ be a nonnegative real number. Is it true that, given the condition $$\sum_{1\le i<j\le6}x_{ij}^2=1,$$ the sum $$\sum_{1\le i<...

I want to compute the projection of a vector $\left( x\right) _{1\leq i,j\leq n}\in \lbrack 0,1]^{n\times n}$ on the following discrete set $$ S=\left\{ x\in \{0,1\}^{n\times n}:x_{i,j}+x_{j,i}\leq 1;\...