Timeline for The Stiefel-Whitney and Pontryagin classes of SO(3)-bundles
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
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| Apr 9, 2011 at 19:09 | comment | added | Paul | @BS, Yes, the assertion is that $P(w_2)=p_1$ mod 4. $P(w_2)=w_2^2$ mod 2 is a property of the Pontriyagin square, and when $H^2(M;Z)$ has no 2-torsion, $w_2$ lifts to a $Z$ class, answering Manuel's question. | |
| Apr 8, 2011 at 19:59 | comment | added | Tim Perutz | A reference is Dold and Whitney's 1959 Annals paper on bundles over 4-dimensional complexes (perhaps someone can consult this paper and post the explanation?). | |
| Apr 8, 2011 at 10:41 | comment | added | BS. | See also this MO question and answsers mathoverflow.net/questions/59593/… | |
| Apr 8, 2011 at 10:40 | comment | added | BS. | I think the square is the Pontryagin square. See eom.springer.de/p/p073810.htm | |
| Apr 8, 2011 at 10:24 | history | asked | Manuel | CC BY-SA 3.0 |