G-Invariant Representations using Coorbits: Injectivity Properties

Abstract: Consider a real vector space $\mathcal{V}$ and a finite group $G$ acting unitarily on $\mathcal{V}$. We study the general problem of constructing a stable embedding whose domain is the quotient of the vector space modulo the group action, and whose target space is a Euclidean space. We construct an embedding $\Psi$ and we study under which assumptions $\Psi$ is injective in the quotient vector space. The embedding scheme we introduce is based on selecting a fixed subset from the sorted orbit $\downarrow\langle{U_gw_i},{x}\rangle_{g \in G}$, where $w_i$ are appropriate vectors.