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| | [No title] (Site not responding. Last check: ) |
 | | If the simplicial set $X$ is the 2-simplex $\Delta2$ with its boundary $\partial \Delta2$ collapsed to a point, then the second Kan/normal/barycentric subdivision $Z = Sd2(X)$ still has non-degenerate 2-simplices that are not embedded, i.e., $Z$ is not a simplicial complex in the obvious way. |
 | | This was asserted in a 1956 Princeton preprint of Barratt's, titled "Simplical and semisimplicial complexes", by an argument involving two subdivisions, and some more. |
 | | It seems to me that after 1970 or so, the algebraic topological interest in simplicial sets shifted entirely to their homotopy theory, rather than their topology, i.e., people were mostly concerned with (weak) homotopy equivalences rather than homeomorphisms of the geometric realizations of simplicial sets. |
| www.lehigh.edu /dmd1/public/www-data/jr1229.txt (451 words) |
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