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To answer a question by Rettich and Serafin, we define a model of set theory in which there exists a locally countable graph on a subset of the real line, which is not generated by a countable family of projective (or even real-ordinal definable, ROD) functions. We also prove that the equi-constructibility graph on the reals is not generated by a countable family of ROD functions in the Solovay model.

生成讲解博客的中文版本

生成AI智能校验的中文版本