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arXiv · 2511.06517

The epimorphism relation among countable groups is a complete analytic quasi-order

Su Gao·Feng Li·André Nies·Gianluca Paolini
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Abstract

We prove that the epimorphism relation is a complete analytic quasi-order on the space of countable groups. In the process, we obtain the result of independent interest that the epimorphism relation on pointed reflexive graphs is complete.

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Su Gao, Feng Li, André Nies, Gianluca Paolini. 2025-11-09. The epimorphism relation among countable groups is a complete analytic quasi-order. https://arxiv.org/abs/2511.06517

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