Lower bounds for the norms of projections with small kernels
Carlo Franchetti · Bulletin of the Australian Mathematical Society · 1992
Popov has recently introduced a class of subspaces of Lp(μ) (μ nonatomic) which generalise the finite codimensional ones, and proved that for p ≠ 2 any projection onto such a subspace has a norm strictly greater than one. In this paper we give the quantitative version of Popov's result computing the best possible lower bound for the norms of the considered projections.