Thursday, August 23, 2012

1208.4587 (Frederick R. Cohen et al.)

On homotopy Brunnian links and the kappa-invariant    [PDF]

Frederick R. Cohen, Rafal Komendarczyk, Clayton Shonkwiler
We provide an alternative proof that Koschorke's kappa-invariant is injective on the set of link homotopy classes of n-component homotopy Brunnian links. The existing proof (by Koschorke) is based on the Pontryagin--Thom theory of framed cobordisms, whereas ours is closer in spirit to techniques based on Habegger and Lin's string links. We frame the result in the language of the rational homotopy Lie algebra of the configuration space of n points in R^3, which allows us to express Milnor's higher linking numbers as homotopy periods of the configuration space.
View original: http://arxiv.org/abs/1208.4587

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