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May
16 |
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Every principal $G$-bundle over a surface is trivial if $G$ is compact and simply connected: reference? Thanks for the answer. Any reference I can take a look at? |
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May
15 |
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answered | Deduce dice configuration knowing 2 adjacent faces |
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May
14 |
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The number of words that can be made by permuting the letters of _MATHEMATICS_ is Example: the number of words that can be made by permuting the letters of BEER is 12. The possibilities are EEBR, EERB, EBER, EREB, EBRE, ERBE, BERE, REBE, BREE, RBEE, BEER, REEB. |
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May
14 |
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awarded | Caucus |
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Apr
25 |
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Every principal $G$-bundle over a surface is trivial if $G$ is compact and simply connected: reference? @EricO.Korman - Thank you, that helps (though I have to think about it a little bit). |
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Apr
23 |
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Every principal $G$-bundle over a surface is trivial if $G$ is compact and simply connected: reference? I am familiar with the fundamental group and with singular and de Rham (co)homology. I can define the higher homotopy groups, but I cannot state any relevant "big theorems" by heart. I think I know what classifying spaces are about, meaning that in particular I more or less know the correspondence between homotopy classes of maps $\Sigma\to BG$ and $G$-bundles over $\Sigma$. I have never really worked with higher homotopy groups. (And I'm aware it may be hard to give a good answer to someone lacking this knowledge.) |
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Apr
23 |
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asked | Every principal $G$-bundle over a surface is trivial if $G$ is compact and simply connected: reference? |
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Apr
13 |
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How to classify principal bundles over a 2 dimensional surface? @HenryT.Horton - If $M$ is 2-dimensional and $N$ is 2-connected, why is $[M,N]=0$? (I'm new to homotopy theory.) |
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Mar
24 |
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awarded | Revival |
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Mar
22 |
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awarded | Nice Question |
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Mar
22 |
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accepted | Characterizing singularities using sheaves of smooth functions |
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Mar
21 |
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answered | Is there a better measure of variation for fractional numbers than standard deviation? |
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Mar
20 |
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Topology of finite complements Hint: if singletons are closed, then so are finite sets. |
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Mar
20 |
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answered | Problem - Sum of digits |
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Mar
20 |
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Characterizing singularities using sheaves of smooth functions The book by Navarro González and Sancho de Salas is great! |
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Mar
20 |
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Algebraic functions @Analyst77 - Added complex case to my answer. |
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Mar
20 |
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revised |
Algebraic functions clarified |
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Mar
20 |
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Algebraic functions @Analyst77 - Aha. This was not clear to me. |
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Mar
20 |
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answered | What algorithms are used to determine the difference of two squares? |
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Mar
20 |
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What algorithms are used to determine the difference of two squares? I'm confused by the question. Where in the Euclidean algorithm does one encounter the difference of two squares? |
