2 problems

Let $se(X)$ denote the self-extension constant of a Banach space $X$, namely the infimum of the constants controlling norm-preserving extensions of operators from closed subspaces…

Let $Y$ be a subspace of $c_0$. Suppose that every bilinear form on $Y$ can be extended to a bilinear form on the whole space $c_0$. The $c_0$-conjecture. Then $Y$ is isomorphic to…