An Oracle with no $\mathrm{UP}$-Complete Sets, but $\mathrm{NP}=\mathrm{PSPACE}$

Fuente: arXiv
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Main Authors: Dingel, David, Egidy, Fabian, Glaßer, Christian
Format: Preprint
Published: 2024
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author Dingel, David
Egidy, Fabian
Glaßer, Christian
author_facet Dingel, David
Egidy, Fabian
Glaßer, Christian
contents We construct an oracle relative to which $\mathrm{NP} = \mathrm{PSPACE}$, but $\mathrm{UP}$ has no many-one complete sets. This combines the properties of an oracle by Hartmanis and Hemachandra [HH88] and one by Ogiwara and Hemachandra [OH93]. The oracle provides new separations of classical conjectures on optimal proof systems and complete sets in promise classes. This answers several questions by Pudlák [Pud17], e.g., the implications $\mathsf{UP} \Longrightarrow \mathsf{CON}^{\mathsf{N}}$ and $\mathsf{SAT} \Longrightarrow \mathsf{TFNP}$ are false relative to our oracle. Moreover, the oracle demonstrates that, in principle, it is possible that $\mathrm{TFNP}$-complete problems exist, while at the same time $\mathrm{SAT}$ has no p-optimal proof systems.
format Preprint
id arxiv_https___arxiv_org_abs_2404_19104
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An Oracle with no $\mathrm{UP}$-Complete Sets, but $\mathrm{NP}=\mathrm{PSPACE}$
Dingel, David
Egidy, Fabian
Glaßer, Christian
Computational Complexity
We construct an oracle relative to which $\mathrm{NP} = \mathrm{PSPACE}$, but $\mathrm{UP}$ has no many-one complete sets. This combines the properties of an oracle by Hartmanis and Hemachandra [HH88] and one by Ogiwara and Hemachandra [OH93]. The oracle provides new separations of classical conjectures on optimal proof systems and complete sets in promise classes. This answers several questions by Pudlák [Pud17], e.g., the implications $\mathsf{UP} \Longrightarrow \mathsf{CON}^{\mathsf{N}}$ and $\mathsf{SAT} \Longrightarrow \mathsf{TFNP}$ are false relative to our oracle. Moreover, the oracle demonstrates that, in principle, it is possible that $\mathrm{TFNP}$-complete problems exist, while at the same time $\mathrm{SAT}$ has no p-optimal proof systems.
title An Oracle with no $\mathrm{UP}$-Complete Sets, but $\mathrm{NP}=\mathrm{PSPACE}$
topic Computational Complexity
url https://arxiv.org/abs/2404.19104