Let (X,d,p) be a metric space with a metric d and a marked point p. We define the set of w-strongly porous at 0 subsets of [0,infty) and prove that the distance set {d(x,p): x in X} is w-strongly porous at 0 if and only if every pretangent space to X at p is bounded.
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机译：令（X，d，p）是具有度量d和标记点p的度量空间。我们定义[0， infty）的0个子集上的w-强多孔的集合，并证明距离集{d（x，p）：x in X}在0且仅当每个X在p处的切线空间是有界的。
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