arXiv
Open Access
2021
Separating Rank Logic from Polynomial Time
Moritz Lichter
Abstrak
In the search for a logic capturing polynomial time the most promising candidates are Choiceless Polynomial Time (CPT) and rank logic. Rank logic extends fixed-point logic with counting by a rank operator over prime fields. We show that the isomorphism problem for CFI graphs over $\mathbb{Z}_{2^i}$ cannot be defined in rank logic, even if the base graph is totally ordered. However, CPT can define this isomorphism problem. We thereby separate rank logic from CPT and in particular from polynomial time.
Penulis (1)
M
Moritz Lichter
Akses Cepat
Informasi Jurnal
- Tahun Terbit
- 2021
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- en
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- arXiv
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- Open Access ✓