Complexité des boréliens à coupes dénombrables
英文摘要：
We give, for each level of complexity L, a Hurewicz-like characterization of the Borel subsets with countable sections of a product of two Polish spaces that cannot become in L by changing the two Polish topologies.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
