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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeMar 24th 2010
• (edited Mar 24th 2010)

created reference-entry on David Roberts' thesis:

(David, I slightly edited your nLab-page, accordingly)

• CommentRowNumber2.
• CommentAuthorDavidRoberts
• CommentTimeMar 24th 2010
Thanks, Urs! I had a look at Whitehead tower in an (infinity,1)-topos and the sections I wrote and they are sketchy as. When I get some time I will tidy things up.
• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeMar 24th 2010
• (edited Mar 24th 2010)

When I get some time I will tidy things up.

That would be nice! I was thinking about working on polishing these paragraphs, but seem to have run out of energy.

You should emphasize that the ordinary pullback of the tangent n-groupoid is just one (useful) model of the homotopy pullback of the point. The homotopy pullback perspective gives the abstract concept, the pullback of the tangent n-groupoid a nice convenient concrete realization.

Motivated by your remarks there, I want to add now somwehere a discussion of how the coskeleton operation on sSet models the notion of n-truncation of objects in the oo-topos $\infty Grpd$. That'll be it for today then, for me.