Heegaard Reducing Spheres for the 3-Sphere
Heegaard Reducing Spheres for the 3-Sphere
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用于 3 球体的 Heegaard 还原球体
DOI:
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发表时间:
2001
期刊:
影响因子:
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通讯作者:
M. Scharlemann
中科院分区:
文献类型:
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作者:
M. Scharlemann
In [4] an invariant in Q/2Z was defined for a knot K with unknotting tunnel γ. An important ingredient in the proof that the invariant depended only on the pair (K,γ) was a characterization, in some sense due to Goeritz [1], of reducing spheres for the genus two Heegaard splitting H1 ∪H2 of S 3. It was shown there that any pair of reducing spheres for H1 ∪H2 can be connected by a sequence of reducing spheres, so that any successive pair in the sequence intersect very simply. Here we will use Powell’s [3] extension of Goeritz’ result similarly to describe reducing spheres for arbitrary genus Heegaard splittings of S3. We begin by extending notation and definitions. Let H1 ∪F H2 be a genus g > 1 Heegaard splitting of S 3. It is well-known that H1 ∪F H2 is the standard genus g splitting (see [6] or [5]) so in particular H1 ∪F H2 is reducible.