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<title>Hongxin Guo — Neckpinch</title><link>https://neckpinch.com/authors/hongxin-guo/</link><description>New arXiv papers by Hongxin Guo, from Neckpinch</description>
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<item><title>An Anisotropic Entropy for the Rotationally Symmetric Ricci Flow</title><link>https://neckpinch.com/papers/2610.37154/</link><guid isPermaLink="false">arxiv:2610.37154</guid><pubDate>Tue, 27 Oct 2026 00:00:00 GMT</pubDate><description>Hongxin Guo, Guozhi Lin — For a rotationally symmetric Ricci flow g(t)=ds²+f(s,t)²g_(Sⁿ⁻¹), n≥3, we study the scale-invariant curvature anisotropy A=1-fₛ²+ffₛₛ introduced by Angenent–Knopf. At the critical power p_*=(n-1)/(n-2), with Φ=sgn(A)|A|^(p_*/2), we prove the distributional identity (∂ₜ−Δ)|A|^(p_*) =−4/n-1 |Φₛ+(n-1)(fₛ)/fΦ|². Integration against a conjugate heat kernel gives an anisotropic entropy formula. As an application, we obtain an entropy threshold for Type-I singularities on Sⁿ: if the entropy associated with a singular-time kernel is at most 1 at an earlier regular time, every tangent flow at the corresponding singular point is a round shrinking sphere. This criterion follows from the 0/1 quantization of the singular-time anisotropic density.</description><category>Ricci flow</category><category>Singularities</category><category>Heat kernel</category><category>Rotational symmetry &amp; warped products</category></item>
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