Research output: Contribution to journal › Article › peer-review
On Urysohn’s ℝ-Tree. / Berestovskii, V. N.
In: Siberian Mathematical Journal, Vol. 60, No. 1, 01.01.2019, p. 10-19.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - On Urysohn’s ℝ-Tree
AU - Berestovskii, V. N.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - In the short note of 1927, Urysohn constructed the metric space R that is nowhere locally separable. There is no publication with indications that R is a (noncomplete) ℝ-tree that has valency c at each point. The author in 1989, as well as Polterovich and Shnirelman in 1997, constructed ℝ-trees isometric to R unaware of the paper by Urysohn. In this paper the author considers various constructions of the ℝ-tree R and of the minimal complete ℝ-tree of valency c including R, as well as the characterizations of ℝ-trees, their properties, and connections with ultrametric spaces.
AB - In the short note of 1927, Urysohn constructed the metric space R that is nowhere locally separable. There is no publication with indications that R is a (noncomplete) ℝ-tree that has valency c at each point. The author in 1989, as well as Polterovich and Shnirelman in 1997, constructed ℝ-trees isometric to R unaware of the paper by Urysohn. In this paper the author considers various constructions of the ℝ-tree R and of the minimal complete ℝ-tree of valency c including R, as well as the characterizations of ℝ-trees, their properties, and connections with ultrametric spaces.
KW - boundary
KW - four-point property
KW - injective hull
KW - left-invariant geodesic metric
KW - submetry
KW - ultrametric
KW - ℝ-tree
KW - R-tree
UR - http://www.scopus.com/inward/record.url?scp=85065259399&partnerID=8YFLogxK
U2 - 10.1134/S0037446619010026
DO - 10.1134/S0037446619010026
M3 - Article
AN - SCOPUS:85065259399
VL - 60
SP - 10
EP - 19
JO - Siberian Mathematical Journal
JF - Siberian Mathematical Journal
SN - 0037-4466
IS - 1
ER -
ID: 20039661