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• CommentRowNumber1.
• CommentAuthorGuest
• CommentTimeNov 12th 2009
Created Dold fibration
• CommentRowNumber2.
• CommentAuthorAndrew Stacey
• CommentTimeNov 12th 2009

You are David Roberts and I claim my 5 pounds!

(At least, if you aren't then someone's impersonating you on the n-lab)

• CommentRowNumber3.
• CommentAuthorAndrew Stacey
• CommentTimeNov 12th 2009

To make up for my frivolity, here's a serious question: is a "Dold fibration" the same thing as a quasi-fibration?

• CommentRowNumber4.
• CommentAuthorGuest
• CommentTimeNov 12th 2009
Next time I'm in Norway...

A quasifibration is different - it is characterised by the property that the canonical maps from each fibre to the corresponding homotopy fibre are all weak homotopy equivalences. I've forgotten if Dold fibrations and quasifibrations are comparable, but looking at the 1958 article by Dold and Thom where quasifibrations are introduced, one gets a long exact sequence in homotopy for those as well. There was a bit of to and fro on the Hopf mailing list in 2001 on this, I should get a more complete transcript than what I have on my hard drive and extract some useful points.

My gut feeling is that quasifibration is a weaker notion, and it looks tempting to guess that Dold fibrations are quasifibrations. But it is late here, and I'm not going to commit myself.

-David Roberts
• CommentRowNumber5.
• CommentAuthorGuest
• CommentTimeNov 12th 2009
Added comment to bottom of Dold fibration about quasifibrations, re previous post.

David Roberts
• CommentRowNumber6.
• CommentAuthorUrs
• CommentTimeNov 12th 2009

You know that it is forbidden (by me, if that matters) to have a useful technical exchange here?

If anyone asks a good question here, like Andrew above, the only allowed answers are

a) it's already on the nLab. See xyz

or

b) I have just typed the answer into this nLab entry: xyz .

• CommentRowNumber7.
• CommentAuthorGuest
• CommentTimeNov 12th 2009
My apologies - I was not aware of that. I will get around to putting the relevant info at quasifibration and Dold fibration soon.

David Roberts
• CommentRowNumber8.
• CommentAuthorAndrew Stacey
• CommentTimeNov 13th 2009

@David: I hope you are aware that Urs was quasi-joking. Also, Urs' remark was more aimed at me since I should have put a query box at the n-lab and said "Query at Dold fibration about relationship to quasi-fibrations".

Apologies to you both: to Urs for not remembering the Rules, to David for leading you astray!

• CommentRowNumber9.
• CommentAuthorUrs
• CommentTimeNov 13th 2009

Yes, I was joking. But I took it David stayed within the role I jokingly assigned to him? Maybe not. Text-mode humour is difficult.

All I mean to say from time to time is: let's not forget to put material on the nLab! :-)

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