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arXiv · 2602.05647

Fundamental solution for higher order homogeneous hypoelliptic operators structured on Hörmander vector fields

Stefano Biagi·Marco Bramanti
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Abstract

We introduce and study a new class of higher order differential operators defined on $\mathbb{R}^{n}$, which are built with Hörmander vector fields, homogeneous w.r.t. a family of dilations (but not left invariant w.r.t. any structure of Lie group) and have a structure such that a suitably lifted version of the operator is hypoelliptic. We call these operators ''generalized Rockland operators''. We prove that these operators are themselves hypoelliptic and, under a natural condition on the homogeneity degree, possess a global fundamental solution $Γ\left( x,y\right) $ which is jointly homogeneous in $\left( x,y\right) $ and satisfies sharp pointwise estimates. Our theory can be applied also to some higher order heat-type operators and their fundamental solutions.

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Stefano Biagi, Marco Bramanti. 2026-07-09. Fundamental solution for higher order homogeneous hypoelliptic operators structured on Hörmander vector fields. https://arxiv.org/abs/2602.05647

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