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СЕМИНАРЫ |
Семинар по геометрической топологии
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Classifying link maps in the four-sphere (II) Э. Ч. Лайтфут |
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Аннотация: This is the second in a series of talks in which we give a careful exposition of a recent ground-breaking paper of Rob Schneiderman and Peter Teichner, The Group of Disjoint 2-Spheres in 4-Space, arXiv:1708.00358. A link map Previously we discussed immersions of surfaces in four-manifolds, finger moves, Whitney disks and Wall's algebraic intersection numbers. In this second talk, we apply these techniques in the setting of link maps, and our goal is two-fold. We first introduce Kirk's link homotopy invariant and investigate its properties. We then introduce a standard (or “unknotted”) form of an immersed 2-sphere in 4-space, and show that any link map may be arranged so that one component is standard. Website: https://arxiv.org/abs/1708.00358
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