The Steiner Mapping for Three Points in Euclidean Plane / K. V. Chesnokova. // Vestnik Moskovskogo Universiteta. Seriya 1. Matematika. Mekhanika. 2018. № 1. P. 20-26 [Moscow Univ. Math. Bulletin. Vol. 72, N 2, 2017. P. 17-23].

For the Euclidean plane \mathbb{C} the Steiner mapping associating any three points a, b, c with their median s, and the corresponding operator P_D of metric projection of the space l_1^3(\mathbb{C}) onto its diagonal subspace D=\{(x, x, x) \colon x \in \mathbb{C}\}, P_D(a, b, c)=(s, s, s) \colon s are considered. The exact value of the linearity coefficient of P_D is calculated.

Key words: linearity coefficient, metric projection, median, Euclidean plane.

№ 1/2018