• 대한수학회보
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• 제36권2호
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• pp.259-272
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• 1999

In [6], Godefroy defined octahedral norms to give an isomorphic characterization of spaces containing $\ell_1$. Here we will show that such norms can be defined by using "average distances" as introduced in[1]. Also, we indicate some other properties of average distances : in particular, we give some estimates for their values in the product of two spaces, furnished with the max or the sum norm.