





















Let $φ(x,y)$ be a continuous function, smooth away from the diagonal, such that, for some $α>0$, the associated generalized Radon transforms \begin{equation} \label{Radon} R_t^φf(x)=\int_{φ(x,y)=t} f(y) ψ(y) dσ_{x,t}(y) \end{equation} map $L^2({\mathbb R}^d) \to L^2_α({\mathbb R}^d)$ for all $t>0$. Let $E$ be a compact subset of ${\mathbb R}^d$ for some $d \ge 2$, and suppose that the Hausdorff dimension of $E$ is $>d-α$. We show that any tree graph $T$ on $k+1$ ($k \ge 1$) vertices is \new{stably} realizable in $E$, in the sense that \new{for each $t$ in some open interval} there exist distinct $x^1, x^2, \dots, x^{k+1} \in E$ %and $t>0$ such that the $φ$-distance $φ(x^i, x^j)=t$ for all pairs $(i,j)$ corresponding to the edges of $T$. We extend this result to trees whose edges are prescribed by more complicated point configurations, such as congruence classes of triangles.
此内容由惯性聚合(RSS阅读器)自动聚合整理,仅供阅读参考。 原文来自 — 版权归原作者所有。