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Estimates of spans of a simple closed curve involving mesh. (English) Zbl 1004.54021

Summary: We show that the dual effectively monotone span of a simple closed curve \(X\) in the plane does not exceed the infimum of the set of positive numbers \(m\) such that a chain with mesh \(m\) covers \(X\). We also include a short direct proof of a known inequality \(\sigma_0(0) \leq\varepsilon(X)\), where \(X\) is a continuum.

MSC:

54F15 Continua and generalizations
54C05 Continuous maps

Keywords:

monotone span