Separation by hyperplanes in finite-dimensional vector spaces over Archimedean ordered fields.
Sets invariant under projections onto one dimensional subspaces
The Hahn–Banach theorem implies that if is a one dimensional subspace of a t.v.s. , and is a circled convex body in , there is a continuous linear projection onto with . We determine the sets which have the property of being invariant under projections onto lines through subject to a weak boundedness type requirement.
Sets of constant width and diametrically complete setes in normed spaces
Smoothness of vector sums of plane convex sets.
Some notes on convex sets.
Spaces of retractions which are homeomorphic to Hilbert space
Strictly extreme and strictly exposed points.