Summaries of articles published in this issue
1979; Springer Nature; Volume: 29; Issue: 2 Linguagem: Inglês
10.21136/cmj.1979.101593
ISSN1572-9141
ResumoIt is proved that every 72(Г^) image of a T^ space is a Ä:-space (an accessibility space) iff the space is compact.Similar type theorems are proved for /:'-spaces, sequential spaces and Fréchet spaces.Various relations are proved including that a Г2 space is Fréchet iff it is a Ä:-space and an accessibility space.MIROSLAV FIEDLER, Praha: Minimal sets of vectors which generate R" with excess k.Czech.Math.J. 29 ( 104), (1979), 187-191.(Original paper.)A new simple proof of the following theorem is given: The smallest set of vectors in an /г-dimensional real vector space R" which generates R^ as its convex hull and preserves this property even after removing any к of these vectors, has cardinality n -\-2k -\-1.Five equivalent theorems are also stated.
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