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arXiv · 1902.06302

Blowup for the nonlinear heat equation with small initial data in scale-invariant Besov norms

Lorenzo Brandolese·Fernando Cortez
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Abstract

We consider the Cauchy problem of the nonlinear heat equation $u_t -\Delta u= u^{b},\ u(0,x)=u_0$, with $b\geq 2$ and $b\in \mathbb{N}$. We prove that initial data $u_0\in \mathcal{S}(\mathbb{R}^{n})$ (the Schwartz class)arbitrarily small in the scale invariant Besov-norm$\dot B^{-2/b}_{n(b-1) b/2,q}(\mathbb{R}^{n})$, can produce solutions that blow up in finite time. The case $b=3$ answers a question raised by Yves Meyer.Our result also proves that the smallness assumption put in an earlier work by C. Miao, B.~Yuan and B. Zhang, for the global-in-time solvability, is essentially optimal.

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Lorenzo Brandolese, Fernando Cortez. 2019-02-17. Blowup for the nonlinear heat equation with small initial data in scale-invariant Besov norms. https://arxiv.org/abs/1902.06302

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