关于次渐近等距于l_1序列

On sequences of sub-asymptotically sometric to l_1

定义了次渐近等距于l1 和l∞ 序列的概念 ,给出了Banach空间有次渐近等距于l1 序列的二个等价条件 .此外 ,还得到Banach空间X有次渐近等距于l1 序列的充分条件是X有子空间与l1 同构 .

The concepts of a sequence of sub asymptotically isometric to l 1 and l ∞ are defined. Two equivalent conditions for a Banach space to contain a sub asymptotically isometric to l 1 are given. In addition, it is tained that a Banach space contains a sub asymptotically isometric to l 1 sequence if X contain a subspace isomorphic to l 1.