John Lindsay Orr


Grothendieck's Inequality

Statement

There exists a universal constant $K$ with the following property. Whenever $(a_{i,j})$ is an $n\times n$ complex matrix which satisfies for all sequences $x_i$, $y_j$ of complex numbers of modulus at most $1$, then also for all sequences $\x_i$, $\y_j$ of vectors in the unit ball of a Hilbert space $\H$.