Conjectured energy-supercritical Type II singularity formation

Let X=({v0}{t0.9}){1u<0}\mathcal{X}=(\{v\leq 0\}\cup \{t\leq -0.9\})\cap\{-1\leq u<0\} and let C\mathcal{C} be the backward light cone. Let ϕ\phi solve the relevant wave-map or semilinear equation, with dd the spatial dimension, pp the power, and cp,dc_{p,d} the constant determined by

p12cp,dp1=d22p1.\frac{p-1}{2}c_{p,d}^{p-1}=d-2-\frac{2}{p-1}.

Let γ=12(d2d28d+8)\gamma=\frac12(d-2-\sqrt{d^2-8d+8}). Energy-supercritical Type II conjecture. For any lN>γl\in\mathbb{N}_{>\gamma} and d7d\geq7, there exists a wave-map solution with k=1k=1 such that ϕC=π2+O(rlγ)\phi|_{\mathcal{C}}=\frac\pi2+\mathcal{O}(r^{l-\gamma}) and ϕ\phi is smooth across C\mathcal{C}. Moreover, for d11d\geq11 and p>1+4d42d1p>1+\frac4{d-4-2\sqrt{d-1}}, after fixing αd,p>0\alpha_{d,p}>0 as in the cited result and taking lN>αl\in\mathbb{N}_{>\alpha}, there exists a solution of the semilinear equation such that

ϕC=cp,dr2p1+O(rlα2p1)\phi|_{\mathcal{C}}=c_{p,d}r^{-\frac2{p-1}}+\mathcal{O}\left(r^{l-\alpha-\frac2{p-1}}\right)

and ϕ\phi is smooth across C\mathcal{C}. The solutions are smooth for v<0v<0 and have scale-critical norm bounded below as τ0\tau\to0; the source further allows finite CkC^k regularity in place of smoothness. These conjectures describe Type II concentration around a singular self-similar exterior profile in the energy-supercritical regime. The supplied text cites constructions but explicitly presents the strengthened regularity formulation as conjectural, and gives no resolution evidence.

Sources & referencesView supporting material

Primary source

Istvan Kadar and Lionor Kehrberger, “A note on exterior stability of isolated singularity formation for nonlinear wave equations”, arXiv:2602.03963 (2026).

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