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1. • CommentRowNumber1.
   • CommentAuthorUrs
   • CommentTimeDec 18th 2014
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   Author: Urs
   Format: MarkdownItexAdded to _[[Klein geometry]]_ a section _[History](http://ncatlab.org/nlab/show/Klein+geometry#History)_ with quotations for where exactly Klein actually speaks about $G/H$. (This key passages is a bit hidden in Klein's text, appearing at a somewhat unexpected point somewhere in the middle of a 35 page document.)

   Added to Klein geometry a section History with quotations for where exactly Klein actually speaks about $G/H$.

   (This key passages is a bit hidden in Klein’s text, appearing at a somewhat unexpected point somewhere in the middle of a 35 page document.)

2. • CommentRowNumber2.
   • CommentAuthornLab edit announcer
   • CommentTimeMar 3rd 2019
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   Author: nLab edit announcer
   Format: MarkdownItex$Iso(d,1)$ contains parity-reversal and time-reversal. To obtain $\mathbb{R}^{d+1}$ from a quotient of $Iso(d,1)$, we must quotient these out. Therefore the stabilizer subgroup $H$ is $O(d,1)$ rather than $SO(d,1)$. Anonymous <a href="https://ncatlab.org/nlab/revision/diff/Klein+geometry/12">diff</a>, <a href="https://ncatlab.org/nlab/revision/Klein+geometry/12">v12</a>, <a href="https://ncatlab.org/nlab/show/Klein+geometry">current</a>

   $Iso(d,1)$ contains parity-reversal and time-reversal. To obtain $\mathbb{R}^{d+1}$ from a quotient of $Iso(d,1)$, we must quotient these out. Therefore the stabilizer subgroup $H$ is $O(d,1)$ rather than $SO(d,1)$.

   Anonymous

   diff, v12, current

3. • CommentRowNumber3.
   • CommentAuthorUrs
   • CommentTimeMar 3rd 2019
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   Author: Urs
   Format: MarkdownItexthanks for catching. It was, luckily, correct in the table right below that erroneous line.

   thanks for catching. It was, luckily, correct in the table right below that erroneous line.

4. • CommentRowNumber4.
   • CommentAuthorUrs
   • CommentTimeApr 11th 2021
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   Author: Urs
   Format: MarkdownItexI have added the publication data and the DOI for the German original, and the projeceuclid-link for the English translation of: * [[Felix Klein]], _[[Vergleichende Betrachtungen über neuere geometrische Forschungen]]_ (1872) Mathematische Annalen volume 43, pages 63–100 1893 ([doi:10.1007/BF01446615](https://doi.org/10.1007/BF01446615)) English translation by M. W. Haskell: _A comparative review of recent researches in geometry_, Bull. New York Math. Soc. 2, (1892-1893), 215-249. ([euclid:1183407629](https://projecteuclid.org/journals/bulletin-of-the-american-mathematical-society-new-series/volume-2/issue-10/A-comparative-review-of-recent-researches-in-geometry/bams/1183407629.full) [[KleinRetyped.pdf:file]], ) will give this its own `category:reference`-page now <a href="https://ncatlab.org/nlab/revision/diff/Klein+geometry/13">diff</a>, <a href="https://ncatlab.org/nlab/revision/Klein+geometry/13">v13</a>, <a href="https://ncatlab.org/nlab/show/Klein+geometry">current</a>

   I have added the publication data and the DOI for the German original, and the projeceuclid-link for the English translation of:

   • Felix Klein, Vergleichende Betrachtungen über neuere geometrische Forschungen (1872) Mathematische Annalen volume 43, pages 63–100 1893 (doi:10.1007/BF01446615)

     English translation by M. W. Haskell:

     A comparative review of recent researches in geometry, Bull. New York Math. Soc. 2, (1892-1893), 215-249. (euclid:1183407629 KleinRetyped.pdf:file, )

   will give this its own category:reference-page now

   diff, v13, current

5. • CommentRowNumber5.
   • CommentAuthorUrs
   • CommentTimeJun 14th 2022
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   Author: Urs
   Format: MarkdownItexI have added a brief example ([here](https://ncatlab.org/nlab/show/Klein+geometry#ExampleCrystallography)) mentioning that the usual study of crystallography through crystallographic symmetry groups is much in the spirit of Klein geometry (even though I have not yet seen an author admitting this). <a href="https://ncatlab.org/nlab/revision/diff/Klein+geometry/15">diff</a>, <a href="https://ncatlab.org/nlab/revision/Klein+geometry/15">v15</a>, <a href="https://ncatlab.org/nlab/show/Klein+geometry">current</a>

   I have added a brief example (here) mentioning that the usual study of crystallography through crystallographic symmetry groups is much in the spirit of Klein geometry (even though I have not yet seen an author admitting this).

   diff, v15, current