Generic dichotomy for homomorphisms for $E_0^{\mathbb{N}}$

Abstract

We prove the following dichotomy. Given an analytic equivalence relation $E$, either $E_0^{\mathbb{N}}{\le }_{B}E$ or else any Borel homomorphism from $E_0^{\mathbb{N}}$ to $E$ is "very far from a reduction", specifically, it factors, on a comeager set, through the projection map $(2^{\mathbb{N}}{)}^{\mathbb{N}}\to (2^{\mathbb{N}}{)}^k$ for some $k\in \mathbb{N}$. As a corollary, we prove that $E_0^{\mathbb{N}}$ is a prime equivalence relation, answering a question on Clemens.