An omega-power of a context-free language which is Borel above Delta^0_omega
英文摘要：
We use erasers-like basic operations on words to construct a set that is both Borel and above Delta^0_omega, built as a set V^ωwhere V is a language of finite words accepted by a pushdown automaton. In particular, this gives a first example of an omega-power of a context free language which is a Borel set of infinite rank.
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。
