Even dimensional surgery obstruction (Ex)
From Manifold Atlas
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Note if there is surgery obstruction that even though we know $\Sigma_g$ is cobordant to $S^2$, the wrong normal map in the surgery programme will not find this cobordism. | Note if there is surgery obstruction that even though we know $\Sigma_g$ is cobordant to $S^2$, the wrong normal map in the surgery programme will not find this cobordism. | ||
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[[Category:Exercises]] | [[Category:Exercises]] | ||
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Latest revision as of 09:16, 1 April 2012
This question is intended to illustrate the importance of the normal map in defining the even-dimensional surgery obstruction.
- Show that any closed, orientable -manifold , possesses a degree 1 map .
- For , find all degree 1 normal maps that cover .
- For each of the , calculate the surgery obstruction . If this vanishes, write down an explicit surgery on that describes a cobordism between and .
Note if there is surgery obstruction that even though we know is cobordant to , the wrong normal map in the surgery programme will not find this cobordism.