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## Discussion Tag Cloud

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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeJan 8th 2016

I have tried to give algebraic topology a better Idea-section.

• CommentRowNumber2.
• CommentAuthorTim_Porter
• CommentTimeJan 9th 2016

One of the links (to the book :Algebraic topology from a homotopical viewpoint) is not working.

• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeJan 11th 2016
• (edited Jan 11th 2016)

Thanks. Maybe better this way. I have replaced it with a pointer to a pdf of just the toc.

• CommentRowNumber4.
• CommentAuthorzskoda
• CommentTimeJan 11th 2016
• (edited Jan 11th 2016)

Urs, I think what you wrote is more suitable to an Overview section rather than the very idea. The idea is to study topological spaces via algebraic invariants or via functors from topological to algebraic categories. Period. Then one can also say that most (though not all, hence e.g. shape theory) useful functors are homotopy invariant.

The rest of the nice story you wrote may belong to an overview of present state of the matters, but not the very idea of the subject. If somebody does not know what algebraic topology is it will not help to hear an explanation via advanced unexplained word “spectral sequence”. I think it would be more sensitive to split the entry into sections Idea and Overview. What do you think ?

• CommentRowNumber5.
• CommentAuthorUrs
• CommentTimeJan 11th 2016

• CommentRowNumber6.
• CommentAuthorzskoda
• CommentTimeJan 13th 2016
• (edited Jan 15th 2016)

I made the splitting and extended the entry algebraic topology significantly. Please take a look.

• CommentRowNumber7.
• CommentAuthorzskoda
• CommentTimeJan 13th 2016

I added few more improvements (I hope).

• CommentRowNumber8.
• CommentAuthorUrs
• CommentTimeJan 13th 2016

Okay, thanks.

(#6 has a typo in the link)

• CommentRowNumber9.
• CommentAuthorDavid_Corfield
• CommentTimeJan 13th 2016

Since ’lifting’ had no link, I started lift with redirects. There will be plenty of links to put in.

• CommentRowNumber10.
• CommentAuthorUrs
• CommentTimeJan 20th 2016
• (edited Jan 20th 2016)

Either it’s a coincidence, or maybe somebody was inspired by the above edits to ask (as you may have seen already) on MathOverflow: What is modern algebraic topology(homotopy theory) about?.

Sometimes I wish the entry hurdle to discussing on the nForum were lower. Are we sure we need to require people to apply for an account here?

• CommentRowNumber11.
• CommentAuthorMike Shulman
• CommentTimeNov 30th 2019

Added a link to Neil Strickland’s interactive demos page.

• CommentRowNumber12.
• CommentAuthorUrs
• CommentTimeNov 26th 2020

have added these pointers:

• CommentRowNumber13.
• CommentAuthorUrs
• CommentTimeNov 28th 2020

• CommentRowNumber14.
• CommentAuthorUrs
• CommentTimeJan 28th 2021

added the pointers to:

• CommentRowNumber15.
• CommentAuthorUrs
• CommentTimeMar 24th 2021

• CommentRowNumber16.
• CommentAuthorUrs
• CommentTimeApr 1st 2021

(despite the title, this is really algebraic topology)

• CommentRowNumber17.
• CommentAuthorUrs
• CommentTimeJul 13th 2021

• CommentRowNumber18.
• CommentAuthorUrs
• CommentTimeSep 18th 2021

• CommentRowNumber19.
• CommentAuthornilesjohnson
• CommentTimeSep 21st 2021

added references under “Books with an emphasis on homotopy theory

• CommentRowNumber20.
• CommentAuthorUrs
• CommentTimeSep 21st 2021

Okay, thanks. Maybe it would be best if I created an !include- page homotopy theory and algebraic topology –references, so that we could edit in a single place and have it automatically synced to both entries. Maybe later.

• CommentRowNumber21.
• CommentAuthornilesjohnson
• CommentTimeSep 21st 2021

Oh, I was thinking about such a thing and didn’t realize it was possible. Yes, probably good, but probably other things are higher priority.

• CommentRowNumber22.
• CommentAuthorUrs
• CommentTimeSep 21st 2021
• (edited Sep 21st 2021)

Okay, I have started homotopy theory and algebraic topology – references, maybe best to further discuss in the thread there

• CommentRowNumber23.
• CommentAuthorUrs
• CommentTimeSep 21st 2021

have now removed the previous content of the section “References” (here) and replaced it by !include-ing homotopy theory and algebraic topology – references.

So to further edit the list of references here, you need to edit there.