Even dimensional surgery obstruction (Ex)
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Revision as of 23:41, 19 March 2012 by Patrickorson (Talk | contribs)
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 and the torus, 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 of the torus to the 2-sphere.
Note if there is surgery obstruction that even though we know the torus is cobordant to the 2-sphere, the wrong normal map in the surgery programme will not find this cobordism.