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Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeApr 12th 2011

I have split off formally etale morphism from etale morphism. Then I added the general-abstract topos theoretic characterization, essentially by copy-and-pasting the discussion from formally smooth morphism (and replacing epimorphisms by isomorphisms)

• CommentRowNumber2.
• CommentAuthorDavidRoberts
• CommentTimeApr 12th 2011

Is equation (1) right at formally etale morphism? In that it has a $\prod$ instead of a $\coprod$

It just looks funny to me, in that you could have used $\times_{blah}$ instead.

• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeApr 12th 2011
• (edited Apr 12th 2011)

it’s supposed to be the fiber product, yes. I thought the bigger the symbol for $blah$, the more reason to use $\prod_{blah}$ instead of $\times_{blah}$! :-)

• CommentRowNumber4.
• CommentAuthorDavidRoberts
• CommentTimeApr 13th 2011

I raised this TeX.SE question in order to pretty up the situation. Unfortunately, the maths I was trying to use didn’t work there, so here it is: $one \sideset{}{_{three}}\prod two$ (in source form, because it doesn’t work here either).

• CommentRowNumber5.
• CommentAuthorDavidRoberts
• CommentTimeApr 13th 2011

Hmm, how about $\prod\nolimits{_a}$

no, that doesn’t work, at least here.

• CommentRowNumber6.
• CommentAuthorUrs
• CommentTimeMar 19th 2012
• (edited Mar 19th 2012)

I have added in the References-section at formally etale morphism a mentioning of Joyal’s lectures from the 1970 where the pullback-definition discussed in the entry apparently first appears (is there any printed trace of these lectures?) and to an article by Dubuc where this is recalled / discussed.

• CommentRowNumber7.
• CommentAuthormaxsnew
• CommentTimeAug 29th 2017
• (edited Aug 29th 2017)
Maybe it's a holdover from previous years, but they were constructed using an explicit html <a> tag instead of the usual markup for cross-referencing on the nlab with double brackets.
As a quick fix, I just replaced nlab.mathforge everywhere with ncatlab.

I don't know if this is a known issue, but it worries me that there might be a lot of these bad links floating around (though I haven't encountered them) so I thought I should bring this to your attention.
• CommentRowNumber8.
• CommentAuthormaxsnew
• CommentTimeAug 29th 2017
Also as to the content of the page, I find the introduction very confusing. The page is about formally etale morphisms, but the first sentence is about formally etale spaces, making the 2nd sentence incongruous and I'm not quite sure how to fix it.
• CommentRowNumber9.
• CommentAuthorRodMcGuire
• CommentTimeAug 29th 2017
• (edited Aug 29th 2017)

This page had several links to nlab.mathforge.org … they were constructed using an explicit html <a> tag instead of the usual markup for cross-referencing on the nlab with double brackets.

I guess whoever made then didn’t know how to link to sections and HowTo#links_to_sections doesn’t help much and really needs to be updated.

In particular one can just use “pipe” naming: [[HowTo#links_to_sections|linking sections]] -> linking sections.

EDIT: I’m now working on updating HowTo#how_to_make_links_to_subsections_of_a_page

• CommentRowNumber10.
• CommentAuthorUrs
• CommentTimeAug 29th 2017

Thanks for the alert in #8. I don’t know what happened there. I have removed the first sentence and added another paragraph. (But I don’t have time to do this entry justice right now).

Regarding the funny links: This is a remnant from the early dates of the $n$Lab. I don’t think there are many of these left.