Automatic and Polynomial-Time Algebraic Structures. / Bazhenov, Nikolay; Harrison-Trainor, Matthew; Kalimullin, Iskander et al.
In: Journal of Symbolic Logic, Vol. 84, No. 4, 01.12.2019, p. 1630-1669.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Automatic and Polynomial-Time Algebraic Structures
AU - Bazhenov, Nikolay
AU - Harrison-Trainor, Matthew
AU - Kalimullin, Iskander
AU - Melnikov, Alexander
AU - Ng, Keng Meng
PY - 2019/12/1
Y1 - 2019/12/1
N2 - A structure is automatic if its domain, functions, and relations are all regular languages. Using the fact that every automatic structure is decidable, in the literature many decision problems have been solved by giving an automatic presentation of a particular structure. Khoussainov and Nerode asked whether there is some way to tell whether a structure has, or does not have, an automatic presentation. We answer this question by showing that the set of Turing machines that represent automata-presentable structures is Σ 1 1-complete. We also use similar methods to show that there is no reasonable characterisation of the structures with a polynomial-time presentation in the sense of Nerode and Remmel.
AB - A structure is automatic if its domain, functions, and relations are all regular languages. Using the fact that every automatic structure is decidable, in the literature many decision problems have been solved by giving an automatic presentation of a particular structure. Khoussainov and Nerode asked whether there is some way to tell whether a structure has, or does not have, an automatic presentation. We answer this question by showing that the set of Turing machines that represent automata-presentable structures is Σ 1 1-complete. We also use similar methods to show that there is no reasonable characterisation of the structures with a polynomial-time presentation in the sense of Nerode and Remmel.
KW - 03D05
KW - 03D45
KW - 03D80
KW - 2010 Mathematics Subject Classification
KW - 68Q45
KW - Primary 03C57
KW - Secondary 03D20
KW - INDEX SETS
KW - FREE ABELIAN-GROUPS
KW - classification
KW - index sets
KW - automatic structures
KW - COMPLEXITY
UR - http://www.scopus.com/inward/record.url?scp=85077331669&partnerID=8YFLogxK
U2 - 10.1017/jsl.2019.26
DO - 10.1017/jsl.2019.26
M3 - Article
AN - SCOPUS:85077331669
VL - 84
SP - 1630
EP - 1669
JO - Journal of Symbolic Logic
JF - Journal of Symbolic Logic
SN - 0022-4812
IS - 4
ER -
ID: 22998175