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تسجيل مستخدم جديدAlmost positive curvature on the Gromoll-Meyer sphere
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Jost-Hinrich Eschenburg
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Gromoll and Meyer have represented a certain exotic 7-sphere $Sigma^7$ as a biquotient of the Lie group $G = Sp(2)$. We show for a 2-parameter family of left invariant metrics on $G$ that the induced metric on $Sigma^7$ has strictly positive sectional curvature at all points outside four subvarieties of codimension $geq 1$ which we describe explicitly.
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