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Lower Semilattices of Separable Congruences of Numbered Algebras. / Kasymov, N. Kh; Morozov, A. S.
In: Siberian Mathematical Journal, Vol. 64, No. 4, 07.2023, p. 864-876.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Lower Semilattices of Separable Congruences of Numbered Algebras
AU - Kasymov, N. Kh
AU - Morozov, A. S.
N1 - The first author was supported by the development program of the Scientific and Education Mathematical Center of Kazan (Volga Region) Federal University (Agreement 075–02–2022–882). The second author was also supported by the Ministry of Science and Higher Education of the Russian Federation (Project FWNF–2022–0012). Публикация для корректировки.
PY - 2023/7
Y1 - 2023/7
N2 - Under study are the closure properties for various classes of separable congruences(in particular, of equivalences)of numbered algebras on the natural numbersunder the upper and lower bounds in the lattice of congruences.We show that the class of all positive congruences forms a sublatticewhereas the classes of negative, computably separable, and separable congruences forma lower but not always an upper subsemilattice.It is shown that uniformly computably separable congruences can fail to formlower and upper semilattices.We give a characterization of semienumerable sets in terms of uniformlycomputably separable equivalences.
AB - Under study are the closure properties for various classes of separable congruences(in particular, of equivalences)of numbered algebras on the natural numbersunder the upper and lower bounds in the lattice of congruences.We show that the class of all positive congruences forms a sublatticewhereas the classes of negative, computably separable, and separable congruences forma lower but not always an upper subsemilattice.It is shown that uniformly computably separable congruences can fail to formlower and upper semilattices.We give a characterization of semienumerable sets in terms of uniformlycomputably separable equivalences.
KW - 510.5
KW - computable completeness
KW - computable separability
KW - congruence lattices of numbered algebras
KW - effectively separable congruences
KW - negative
KW - numbered algebras and morphisms
KW - positive
KW - separability
KW - uniformly computably separable congruences
UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85165583657&origin=inward&txGid=b63c77a2cb8d30916809b4bd8ba7e45b
UR - https://www.mendeley.com/catalogue/330e1b0b-ee51-349d-90e4-a768f22bda7e/
U2 - 10.1134/S0037446623040080
DO - 10.1134/S0037446623040080
M3 - Article
VL - 64
SP - 864
EP - 876
JO - Siberian Mathematical Journal
JF - Siberian Mathematical Journal
SN - 0037-4466
IS - 4
ER -
ID: 59258632