Spread of balleans
Keywords:Ballean, Pseudodiscrete subset, Density, Cellularity, Spread
A ballean is a set endowed with some family of balls in such a way that a ballean can be considered as an asymptotic counterpart of a uniform topological space. We introduce and study a new cardinal invariant called the spread of a ballean. In particular, we show that, for every ordinal ballean B, spread of B coincides with density of B.
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