Degrees of bi-embeddable categoricity. / Bazhenov, Nikolay; Fokina, Ekaterina; Rossegger, Dino et al.
In: Computability, Vol. 10, No. 1, 2021, p. 1-16.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Degrees of bi-embeddable categoricity
AU - Bazhenov, Nikolay
AU - Fokina, Ekaterina
AU - Rossegger, Dino
AU - San Mauro, Luca
N1 - Funding Information: N. Bazhenov was supported by Russian Science Foundation, project No. 18-11-00028. D. Rossegger was supported by RFBR, project no. 17-31-50026 mol_nr. E. Fokina was supported by the Austrian science fund FWF, project P 27527. L. San Mauro was supported by the Austrian science fund FWF, projects P 27527 and M 2461. Publisher Copyright: © 2021-IOS Press. All rights reserved. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021
Y1 - 2021
N2 - We investigate the complexity of embeddings between bi-embeddable structures. In analogy with categoricity spectra, we define the bi-embeddable categoricity spectrum of a structure A as the family of Turing degrees that compute embeddings between any computable bi-embeddable copies of A; the degree of bi-embeddable categoricity of A is the least degree in this spectrum (if it exists). We extend many known results about categoricity spectra to the case of bi-embeddability. In particular, we exhibit structures without degree of bi-embeddable categoricity, and we show that every degree d.c.e above 0 ( α ) for α a computable successor ordinal and 0 ( λ ) for λ a computable limit ordinal is a degree of bi-embeddable categoricity. We also give examples of families of degrees that are not bi-embeddable categoricity spectra.
AB - We investigate the complexity of embeddings between bi-embeddable structures. In analogy with categoricity spectra, we define the bi-embeddable categoricity spectrum of a structure A as the family of Turing degrees that compute embeddings between any computable bi-embeddable copies of A; the degree of bi-embeddable categoricity of A is the least degree in this spectrum (if it exists). We extend many known results about categoricity spectra to the case of bi-embeddability. In particular, we exhibit structures without degree of bi-embeddable categoricity, and we show that every degree d.c.e above 0 ( α ) for α a computable successor ordinal and 0 ( λ ) for λ a computable limit ordinal is a degree of bi-embeddable categoricity. We also give examples of families of degrees that are not bi-embeddable categoricity spectra.
KW - Bi-embeddability
KW - categoricity
KW - computable categoricity
KW - computable structures
UR - http://www.scopus.com/inward/record.url?scp=85099947227&partnerID=8YFLogxK
U2 - 10.3233/COM-190289
DO - 10.3233/COM-190289
M3 - Article
AN - SCOPUS:85099947227
VL - 10
SP - 1
EP - 16
JO - Computability
JF - Computability
SN - 2211-3568
IS - 1
ER -
ID: 27640302