A simple formula showing L¹ is a maximal overspace for two-dimensional real spaces
It follows easily from a result of Lindenstrauss that, for any real twodimensional subspace v of L¹, the relative projection constant λ(v;L¹) of v equals its (absolute) projection constant . The purpose of this paper is to recapture this result by exhibiting a simple formula for a subspace V contained in and isometric to v and a projection from C ⊕ V onto V such that , where P₁ is a minimal projection from L¹(ν) onto v. Specifically, if , then , where and .