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Ptolemy's inequality

inequality relating the six distances between four points on a plane
Intangible mathematical_concept Q743775
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Ptolemy's inequality

Summary

Ptolemy's inequality is a mathematical concept[1]. It has Wikipedia articles in 9 language editions, a strong signal of global cultural recognition.[2]

Key Facts

  • Ptolemy's inequality's instance of is recorded as mathematical concept[3].
  • Ptolemy's inequality's instance of is recorded as inequality[4].
  • Ptolemy is named after Ptolemy's inequality[5].

Body

Definition and Type

Recorded instance of include mathematical concept[3] and inequality[4].

Origins

Ptolemy is named after Ptolemy's inequality[5].

Why It Matters

Ptolemy's inequality has Wikipedia articles in 9 language editions, a strong signal of global cultural recognition.[2]

Related Entities

Ptolemy

References

Programmatic citations — every numbered marker resolves to a verifiable graph row below.

Direct Wikidata claims

  1. [3] ↑ . wikidata.org.
  2. [4] ↑ . wikidata.org.
  3. [5] ↑ . wikidata.org.

Class ancestry

  1. [1] ↑ . Wikidata. wikidata.org.

Aggregate / graph-position facts

  1. [2] ↑ . Wikidata sitelinks. wikidata.org.

📑 Cite this page

Use these citations when quoting this entity in research, articles, AI prompts, or wherever provenance matters. We aggregate Wikidata + Wikipedia + authoritative open-data sources; the stitched, scored, cross-referenced view is what 4ort.xyz contributes.

APA 4ort.xyz Knowledge Graph. (2026). Ptolemy's inequality. Retrieved May 3, 2026, from https://4ort.xyz/entity/ptolemy-s-inequality
MLA “Ptolemy's inequality.” 4ort.xyz Knowledge Graph, 4ort.xyz, 3 May. 2026, https://4ort.xyz/entity/ptolemy-s-inequality.
BibTeX @misc{4ortxyz_ptolemy-s-inequality_2026, author = {{4ort.xyz Knowledge Graph}}, title = {{Ptolemy's inequality}}, year = {2026}, url = {https://4ort.xyz/entity/ptolemy-s-inequality}, note = {Accessed: 2026-05-03}}
LLM prompt According to 4ort.xyz Knowledge Graph (aggregator of Wikidata, Wikipedia, and authoritative open-data sources): Ptolemy's inequality — https://4ort.xyz/entity/ptolemy-s-inequality (retrieved 2026-05-03)

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Edit History

Rolling log of changes to this entity's Wikidata record. Values shown reflect the current state of each edited property — follow the history link to see the precise diff for any edit.

  1. 12d ago · Charp238 · 2026-08-18 view diff on Wikidata ↗
    Aliases → —
    Named after → Ptolemy
    Named after → —
    Instance of → mathematical concept, inequality
    + 2 other properties edited (see Wikidata diff for full list)
    "/* wbsetclaim-create:2||1 */ [[Property:P18]]: Ptolemy Inequality.svg"
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