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JOURNALS // Sibirskie Èlektronnye Matematicheskie Izvestiya [Siberian Electronic Mathematical Reports] // Archive

Sib. Èlektron. Mat. Izv., 2023 Volume 20, Issue 1, Pages 501–513 (Mi semr1594)

Mathematical logic, algebra and number theory

The complexity of quasivariety lattices. II

M. V. Schwidefsky

Novosibirsk State University, Pirogova str. 1, 630090, Novosibirsk, Russia

Abstract: We prove that if a quasivariety $\mathbf{K}$ contains a finite $\mathrm{B}^\ast$-class relative to some subquasivariety and some variety possessing some additional property, then $\mathbf{K}$ contains continuum many $Q$-universal non-profinite subquasivarieties having an independent quasi-equational basis as well as continuum many $Q$-universal non-profinite subquasivarieties having no such basis.

Keywords: inverse limit, quasi-equational basis, quasivariety, profinite structure, profinite quasivariety.

UDC: 515.57

MSC: 08C15, 54H99, 03C60, 08A30

Received March 20, 2022, published July 18, 2023

Language: English

DOI: 10.33048/semi.2023.20.030



© Steklov Math. Inst. of RAS, 2025