Minimal projections onto some subspaces of \(\ell_1^{(n)}\)
Let \(P(X,V)\) be the set of all projections from the Banach space \(X\) onto its subspace \(V\). Let \[ \lambda(V,X)= \inf\{\| P\|: P\in P(X,V)\}\quad\text{and} \quad \lambda(V)= \sup\{\lambda(V,X): V\subset X\}. \] In this note, the authors calculate the norm of minimal projections \(\| P\|= \lambda(V,X)\) when \(X= \ell^{(n)}_1\) and \(V\) some symmetric subspace.
scientific article; zbMATH DE number 1251473