Page 1 Next

Displaying 1 – 20 of 25

Showing per page

Sets invariant under projections onto one dimensional subspaces

Simon Fitzpatrick, Bruce Calvert (1991)

Commentationes Mathematicae Universitatis Carolinae

The Hahn–Banach theorem implies that if m is a one dimensional subspace of a t.v.s. E , and B is a circled convex body in E , there is a continuous linear projection P onto m with P ( B ) B . We determine the sets B which have the property of being invariant under projections onto lines through 0 subject to a weak boundedness type requirement.

Some characterization of locally nonconical convex sets

Witold Seredyński (2004)

Czechoslovak Mathematical Journal

A closed convex set Q in a local convex topological Hausdorff spaces X is called locally nonconical (LNC) if for every x , y Q there exists an open neighbourhood U of x such that ( U Q ) + 1 2 ( y - x ) Q . A set Q is local cylindric (LC) if for x , y Q , x y , z ( x , y ) there exists an open neighbourhood U of z such that U Q (equivalently: b d ( Q ) U ) is a union of open segments parallel to [ x , y ] . In this paper we prove that these two notions are equivalent. The properties LNC and LC were investigated in [3], where the implication L N C L C was proved in general, while...

Sur la frontière d'un convexe mobile

Manuel D.P. Monteiro Marques (1984)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Siano A , B sottoinsiemi convessi, chiusi e limitati di uno spazio normato X , con le frontiere f r A , f r B . Dimostriamo che h ( A , B ) = h ( f r A , f r B ) , dove h è la metrica di Hausdorff tra sottoinsiemi chiusi di X . Studiamo inoltre la continuità e la semicontinuità superiore ed inferiore di una multifunzione di tipo «frontiera».

Currently displaying 1 – 20 of 25

Page 1 Next