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Happy Ending problem

problem about proving that five points in the plane will have a subset forming the vertices of a convex quadrilateral
Thing mathematical_problem Q1033772
Happy Ending problem
David Eppstein at English Wikipedia · Public Domain · Wikimedia
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Happy Ending problem

Summary

Happy Ending problem is a mathematical problem[1]. It draws 113 Wikipedia views per month (mathematical_problem category, ranking #30 of 128).[2]

Key Facts

  • Happy Ending problem's image is recorded as Happy-End-problem.svg[3].
  • Happy Ending problem's instance of is recorded as mathematical problem[4].
  • happy ending is named after Happy Ending problem[5].
  • Happy Ending problem's Freebase ID is recorded as /m/07p47h[6].
  • Happy Ending problem's MathWorld ID is recorded as HappyEndProblem[7].
  • Happy Ending problem's maintained by WikiProject is recorded as WikiProject Mathematics[8].
  • Happy Ending problem's Microsoft Academic ID is recorded as 113986443[9].
  • Happy Ending problem's Encyclopedia of China is recorded as 109705[10].
  • Happy Ending problem's Erdős Problem number is recorded as 107[11].

Why It Matters

Happy Ending problem draws 113 Wikipedia views per month (mathematical_problem category, ranking #30 of 128).[2] It has Wikipedia articles in 14 language editions, a strong signal of global cultural recognition.[12] It is known by 5 alternative names across languages and contexts.[13]

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.
  4. [6] ↑ . Freebase Data Dumps. wikidata.org.
  5. [7] ↑ . wikidata.org.
  6. [8] ↑ . wikidata.org.
  7. [9] ↑ . wikidata.org.
  8. [10] ↑ . wikidata.org.
  9. [11] ↑ . wikidata.org.

Class ancestry

  1. [1] ↑ . Wikidata. wikidata.org.

Aggregate / graph-position facts

  1. [2] ↑ . Wikimedia Foundation. dumps.wikimedia.org.
  2. [12] ↑ . Wikidata sitelinks. wikidata.org.
  3. [13] ↑ . Wikidata aliases. 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). Happy Ending problem. Retrieved May 3, 2026, from https://4ort.xyz/entity/happy-ending-problem
MLA “Happy Ending problem.” 4ort.xyz Knowledge Graph, 4ort.xyz, 3 May. 2026, https://4ort.xyz/entity/happy-ending-problem.
BibTeX @misc{4ortxyz_happy-ending-problem_2026, author = {{4ort.xyz Knowledge Graph}}, title = {{Happy Ending problem}}, year = {2026}, url = {https://4ort.xyz/entity/happy-ending-problem}, note = {Accessed: 2026-05-03}}
LLM prompt According to 4ort.xyz Knowledge Graph (aggregator of Wikidata, Wikipedia, and authoritative open-data sources): Happy Ending problem — https://4ort.xyz/entity/happy-ending-problem (retrieved 2026-05-03)

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