Fractional operators and Sobolev spaces on homogeneous groups
We establish foundational properties of fractional operators on Lie groups of homogeneous type. We prove embedding theorems for the associated Sobolev-type spaces.
arXiv subjects
Publications and source records attributed to Annunziata Loiudice.
We establish foundational properties of fractional operators on Lie groups of homogeneous type. We prove embedding theorems for the associated Sobolev-type spaces.
We study the following class of quasilinear degenerate elliptic equations with critical nonlinearity \begin{align*} \begin{cases}-Δ_{γ,p} u= λ|u|^{q-2}u+|u|^{p_γ^{*}-2}u & \text{ in } Ω\subset \mathbb{R}^N, \\ u=0 & \text{ on } \partial Ω, \end{cases} \end{align*} where $Δ_{γ, p}v:=\sum_{i=1}^N X_i(|\nabla_γu|^{p-2}X_i u)$ is the Grushin $p$-Laplace operator, $z:=(x, y) \in \mathbb{R}^N$, $N=m+n,$ $m,n \geq 1,$, where $\nabla_γ=(X_1, \ldots, X_N)$ is the Grushin gradient, defined as the system of vector fields $X_i=\frac{\partial}{\partial x_i}, i=1, \ldots, m$, $X_{m+j}=|x|^γ\frac{\partial}{\partial y_j}, j=1, \ldots, n$, where $γ>0$. Here, $Ω\subset \mathbb{R}^{N}$ is a smooth bounded domain such that $Ω\cap \{x=0\}\neq \emptyset$, $λ>0$, $q \in [p,p_γ^*)$, where $p_γ^{*}=\frac{pN_γ}{N_γ-p}$ and $N_γ=m+(1+γ)n$ denotes the homogeneous dimension attached to the Grushin gradient. The results extends to the $p$-case the Brezis-Nirenberg type results in Alves-Gandal-Loiudice-Tyagi [J. Geom. Anal. 2024, 34(2),52]. The main crucial step is to preliminarily establish the existence of the extremals for the involved Sobolev-type inequality \begin{equation*} \int_{\mathbb{R}^N} |\nabla_γ u|^p dz \geq S_{γ,p} \left ( \int_{\mathbb{R}^N} |u|^{p_γ^*} dz \right )^{p/p_γ^*} \end{equation*} and their qualitative behavior as positive entire solutions to the limit problem \begin{equation*} -Δ_{γ,p} u= u^{p_γ^{*}-1}\quad \mbox{on}\, \mathbb{R}^N, \end{equation*} whose study has independent interest.
In this paper we establish the sharp asymptotic decay of positive solutions of the Yamabe type equation $\frlap u=u^{\frac{Q+2s}{Q-2s}}$ in a homogeneous Lie group, where $\frlap$ represents a suitable pseudodifferential operator modelled on a class of nonlocal operators arising in conformal CR geometry.