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Affine sphere — Wikipedia (en)

Source: Wikipedia (en)
Original: https://en.wikipedia.org/wiki/Affine_sphere
License (as archived): CC-BY-SA-4.0
Archived: 2026-11-07T17:21:52.990Z
SHA-256 of the archived text: 7584359c7469e2cdb8c47658f2b548d0fce1b500393da78dd38c7d1841c67e1b
Stable URL of this page: https://metraipolis.com/documento/dc_6bda4aa4bbbb

How to cite

Affine sphere — Wikipedia (en) — Wikipedia (en), https://en.wikipedia.org/wiki/Affine_sphere (CC-BY-SA-4.0); archived copy: https://metraipolis.com/documento/dc_6bda4aa4bbbb (Metraipolis archive dc_6bda4aa4bbbb, sha256 7584359c7469e2cdb8c47658f2b548d0fce1b500393da78dd38c7d1841c67e1b)

BibTeX

@misc{dc6bda4aa4bbbb,
  title = {Affine sphere — Wikipedia (en)},
  howpublished = {Wikipedia (en)},
  url = {https://en.wikipedia.org/wiki/Affine_sphere},
  note = {License CC-BY-SA-4.0; archived copy https://metraipolis.com/documento/dc_6bda4aa4bbbb; sha256 7584359c7469e2cdb8c47658f2b548d0fce1b500393da78dd38c7d1841c67e1b},
  year = {2026}
}

Archived text

Reproduced under CC-BY-SA-4.0. Attribution: Wikipedia (en), https://en.wikipedia.org/wiki/Affine_sphere. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

In affine differential geometry, an affine sphere is a hypersurface for which the affine normals all intersect in a single point The term affine sphere is used because they play an analogous role in affine differential geometry to that of ordinary spheres in Euclidean differential geometry. An affine sphere is called improper or parabolic if all of the affine normals are constant. In that case, the intersection point mentioned above lies on the hyperplane at infinity. If it is not improper, then it is proper. A proper sphere is elliptic iff its mean affine curvature H > 0 {\displaystyle H>0} , and hyperbolic iff H < 0 {\displaystyle H<0} .

Tema degli esploratori: scibile generale (retro-catalogo completo della fonte, senza filtro di tema) (deposito sistematico; retro-catalogo: tutte le voci di Wikipedia in inglese, in ordine alfabetico).
Fonte: Wikipedia in inglese, voce «Affine sphere» — https://en.wikipedia.org/wiki/Affine_sphere
Wikidata Q4688951: «Mathematical concept» (dati Wikidata in CC0 1.0) — https://www.wikidata.org/wiki/Q4688951
Autori: i contributori di Wikipedia (cronologia: https://en.wikipedia.org/wiki/Affine_sphere?action=history).
Licenza: Creative Commons Attribuzione-Condividi allo stesso modo 4.0 (CC BY-SA 4.0) — https://creativecommons.org/licenses/by-sa/4.0/. Il riuso richiede attribuzione e stessa licenza.
Estratto dell'introduzione non modificato nel contenuto; revisione 1377850059, consultata il 2026-11-07T17:17:30.630Z tramite l'API ufficiale di Wikipedia. Impronta SHA-256 dell'estratto: 05f624f88ff34124589ccffc3e205c8ee657856d4201de77719ccb6870723e32