Talk:Strictly convex space

Latest comment: 6 years ago by 95.182.248.9

I see a problem with this definition:

a strictly convex space is one for which, given any two points x and y in the boundaryB of the unit ball B of V, the affine line L(xy) passing through x and y meets ∂B only at x and y.

The problematic case is when the V vector space is over the field of complex numbers. The affine line is a shifted one-dimensional linear subspace, but in the complex case this is topologically a 2-dimensional manifold. So according this definition with norm is not strictly convex, because each affine line is itself, so it meets the unit sphere in more than 2 points. However, this is an inner product space, so it should be stricly convex. 89.135.19.250 (talk) 06:59, 14 March 2013 (UTC)Reply


The properties are valid in any normed vector space, not just a Banach space. — Preceding unsigned comment added by 95.182.248.9 (talk) 15:28, 2 June 2018 (UTC)Reply