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# Questions

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### Contractible noncompact 3-manifold without boundary not homeomorphic to $\Bbb R^3$

nov 25 11 at 1:18 lethe 44838

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### $V$, $W$ are varieties. Does $V\times \mathbf{P}^1=W\times \mathbf{P}^1$ imply $V=W$?

oct 15 11 at 23:30 Francesco Polizzi 19k23455

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### How does all of the bundles over a certain manifold characterize the homotopy class of the base manifold?

apr 21 11 at 7:36 Oscar Randal-Williams 5,15511226

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### Can a smooth, immersed loop in R^2 become not nullhomotopic by removing a point?

mar 12 11 at 10:33 Bruno Martelli 4,73211233

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