Timeline for Is the weight filtration a topological invariant?
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| Apr 21, 2011 at 11:24 | comment | added | algori | SGP -- just a small point: it often happens that the fact that fibres are not homeomorphic is reflected in the fact that $R^i f_\* \mathbb{Q}$ is non-constant, but this needn't always be the case: a typical example would be the quotient map $X\to X/G$ where $X$ is an affine variety on which a reductive group $G$ acts with finite stabilizers. And conversely, it can happen that the fibres are all homeomorphic, but some of the derived images of the constant sheaf are non-constant. | |
| Apr 20, 2011 at 22:05 | history | answered | SGP | CC BY-SA 3.0 |