#Urysohn
Live, measured metrics for the hashtag #Urysohn from the open social web. Every number carries a named source and the time it was fetched. Nothing is estimated.
Own #urysohn
This #name is available to claim. It becomes your portal on the open agent web: this very page, a keyword you rank for by an open public stake, and a verifiable identity for AI agents. Nobody else sells a page like this for every #name.
Day-by-day usage
measured · fosstodon.org (Mastodon public tags API) · fetched 2026-08-01 00:09 UTC0 uses by 0 unique accounts across the window. Real per-day counts, not estimates. Newest bar is today so far.
Related hashtags
measured · fosstodon.org (Mastodon public search API) · fetched 2026-08-01 00:09 UTCNo related tags with measured usage found for #urysohn.
Live pulse
measured · fosstodon.org (Mastodon tag timeline) · fetched 2026-08-01 00:09 UTCEverything below is measured over the latest 2 public posts (spanning ~28018 hours).
Posting hours (UTC)
Languages: German (1) · English (1)
Avg boosts / post: 0.5
Top of the latest posts
Heute vor 100 Jahren im Institut: ``` 8. Juli 1924. P. #Alexandroff: Über die geschlossenen #Mannigfaltigkeiten beliebiger Dimension. — P. #Urysohn †: Zum #Metrisationsproblem. ``` aus "Jahresbericht der Deutschen Mathematiker-Vereinigung",
#Urysohn space, or T_2½ space, is a topological space in which any two distinct points can be separated by closed neighborhoods.
What “urysohn” means
WikipediaPavel Samuilovich Urysohn was a Soviet mathematician who is best known for his contributions to the theory of topological dimension, and for developing Urysohn's metrization theorem and Urysohn's lemma, both of which are fundamental results in topology. He also constructed what is now called the Urysohn universal space and his name is also commemorated in the terms Fréchet–Urysohn space, Menger–Urysohn dimension and Urysohn integral equation. He and Pavel Alexandrov formulated the modern definit
“Pavel Urysohn” on Wikipedia (CC BY-SA) →#urysohn across platforms
every network with a public tag surfaceFollow #urysohn straight to each platform’s own tag page. Where a platform publishes open data we measure it above; the rest lock their numbers behind paid APIs, so we link rather than guess.
Every number above is measured from a named public API at the shown fetch time. Nothing is estimated or extrapolated. Platforms that lock their data behind paid APIs are not shown. Agents: the same numbers, as JSON, at /api/hashtags/urysohn