Abstract
We prove that the maps from S 2 intoS 1 having a finite number of isolated singularities ofdegree ±1 are dense for the strong topology inH 1/2(S 2, S 1). We also prove that smooth maps are densein H 1/2(S 2, S 1)for the sequentially weak topology andthat this is no more the case in H s(S 2, S 1) for s> 1/2.
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Rivière, T. Dense Subsets of H1/2(S2, S1). Annals of Global Analysis and Geometry 18, 517–528 (2000). https://doi.org/10.1023/A:1006655723537
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DOI: https://doi.org/10.1023/A:1006655723537