4 citations · 24 across the 23 of their papers we have counts for
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A non-Archimedean Arens--Eells isometric embedding theorem on valued fields
Yoshito Ishiki
In 1959, Arens and Eells proved that every metric space can be isometrically embedded into a normed linear space as a closed subset. In later years, in the paper on a short proof o…
Characterizations of Urysohn universal ultrametric spaces
Yoshito Ishiki
In this paper, using the existence of infinite equidistant subsets of closed balls, we characterize the injectivity of ultrametric spaces for finite ultrametric spaces, which also…
Constructions of Urysohn universal ultrametric spaces
Yoshito Ishiki
In this paper, we give new constructions of Urysohn universal ultrametric spaces. We first characterize a Urysohn universal ultrametric subspace of the space of all continuous func…
Uniqueness and homogeneity of non-separable Urysohn universal ultrametric spaces
Yoshito Ishiki
Urysohn constructed a separable complete universal metric space homogeneous for all finite subspaces, which is today called the Urysohn universal metric space. Some authors have re…