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$K$-Bad Spheres

In this paper we look at the $E$-completion of topological spaces where $E$ is a $p$-local ring spectrum. After a brief review of the concept of $E$-completion, we specialize to the case where $E=K$, $p$-local complex periodic $K$-theory, and consider the $K$-theory of the unstable sphere $S^{2n+1}$. We show that for certain values of $n$ and an odd prime $p$, the $K$-homology of the $K$-completion is not isomorphic to the $K$-homology of the sphere itself, thus in the terminology of Bousfield and Kan, these spheres are '$K$-bad'.

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Co-authorshipAuthorshipAuthorshipTopic signalW$K$-Bad Spherespreprint / 2026AMartin BenderskyResearcherARobert ThompsonResearcherTmath.AT1949 works
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$K$-Bad Spheres

preprint / 2026

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