Abstract:
We study the connection between the set of Steiner points for a four-element set and the set of Steiner points for a three-element subset in $L_1$-predual spaces. A Lipschitz selection is presented for the mapping from fours of continuous functions on a Hausdorff compact set to the set of their Steiner points.
Key words:Banach space, Lindenstrauss space, Steiner point, Lipschits selection.