Degrees of categoricity and spectral dimension. / Bazhenov, Nikolay A.; Kalimullin, Iskander S.H.; Yamaleev, Mars M.
In: Journal of Symbolic Logic, Vol. 83, No. 1, 01.03.2018, p. 103-116.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Degrees of categoricity and spectral dimension
AU - Bazhenov, Nikolay A.
AU - Kalimullin, Iskander S.H.
AU - Yamaleev, Mars M.
N1 - Publisher Copyright: © 2018 The Association for Symbolic Logic. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2018/3/1
Y1 - 2018/3/1
N2 - A Turing degree d is the degree of categoricity of a computable structure S if d is the least degree capable of computing isomorphisms among arbitrary computable copies of S. A degree d is the strong degree of categoricity of S if d is the degree of categoricity of S, and there are computable copies A and B of S such that every isomorphism from A onto B computes d. In this paper, we build a c.e. degree d and a computable rigid structure Msuch that d is the degree of categoricity of M, but d is not the strong degree of categoricity of M. This solves the open problem of Fokina, Kalimullin, andMiller [13]. For a computable structure S, we introduce the notion of the spectral dimension of S, which gives a quantitative characteristic of the degree of categoricity of S. We prove that for a nonzero natural number N, there is a computable rigid structureMsuch that 0 is the degree of categoricity ofM, and the spectral dimension ofMis equal to N.
AB - A Turing degree d is the degree of categoricity of a computable structure S if d is the least degree capable of computing isomorphisms among arbitrary computable copies of S. A degree d is the strong degree of categoricity of S if d is the degree of categoricity of S, and there are computable copies A and B of S such that every isomorphism from A onto B computes d. In this paper, we build a c.e. degree d and a computable rigid structure Msuch that d is the degree of categoricity of M, but d is not the strong degree of categoricity of M. This solves the open problem of Fokina, Kalimullin, andMiller [13]. For a computable structure S, we introduce the notion of the spectral dimension of S, which gives a quantitative characteristic of the degree of categoricity of S. We prove that for a nonzero natural number N, there is a computable rigid structureMsuch that 0 is the degree of categoricity ofM, and the spectral dimension ofMis equal to N.
KW - categoricity spectrum
KW - computable categoricity
KW - degree of categoricity
KW - rigid structure
UR - http://www.scopus.com/inward/record.url?scp=85046365456&partnerID=8YFLogxK
U2 - 10.1017/jsl.2017.70
DO - 10.1017/jsl.2017.70
M3 - Article
AN - SCOPUS:85046365456
VL - 83
SP - 103
EP - 116
JO - Journal of Symbolic Logic
JF - Journal of Symbolic Logic
SN - 0022-4812
IS - 1
ER -
ID: 13072386