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arXiv · 2301.06349

Second order commutator estimates in renormalisation theory for SPDEs with gradient-type noise

Peter H. C. Pang
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Abstract

An important step in standard renormalisation arguments involve convolution against a standard mollifier. As pointed out in (Punshon-Smith--Smith 2018), this generates second order commutator terms in equations with gradient-type noise. These are commutators similar to commutators in the well-known ``folklore lemma" of Di Perna--Lions (Di Perna--Lions 1989, Lemma II.1), but not covered by standard renormalisation theory. In this note we establish the vanishing of these commutators for gradient-type noises on $\mathbb{T}^d$ not necessarily possessing divergence-free structure.

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Peter H. C. Pang. 2023-01-16. Second order commutator estimates in renormalisation theory for SPDEs with gradient-type noise. https://arxiv.org/abs/2301.06349

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