The connections between the set of geometric medians for a four-element set and the set of Steiner points for its three-element subsets in L₁-predual spaces are studied. A Lipschitz selection for the mapping from quadruples of continuous functions on a Hausdorff compact space to the set of their geometric medians is presented.

中文翻译：

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Lindenstrauss空间中四元素子集的几何中值集

研究了四元素集的几何中位数集与其三元素子集的斯坦纳点集在L _1-前置空间中的联系。提出了Lipschitz选择，用于从Hausdorff紧致空间上的四个连续函数到其几何中位数的映射。