Recursively Undecidable Properties of NP
<|reference_start|>Recursively Undecidable Properties of NP: We show that there cannot be any algorithm that for a given nondeterministic polynomial-time Turing machine determinates whether or not the language recognized by this machine belongs to P<|reference_end|>
@article{naidenko2001recursively,
    title={Recursively Undecidable Properties of NP},
    author={V.G. Naidenko},
    journal={arXiv preprint arXiv:cs/0106049},
    year={2001},
    archivePrefix={arXiv},
    eprint={cs/0106049},
    primaryClass={cs.CC}
}