Results 21 to 30 of about 494 (99)
Almost structural completeness; an algebraic approach [PDF]
, 2014 A deductive system is structurally complete if its admissible inference rules are derivable. For several important systems, like modal logic S5, failure of structural completeness is caused only by the underivability of passive rules, i.e. rules that can
M. Stronkowski, Michał, Wojciech Dzik
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Finite atomistic lattices that can be represented as lattices of quasivarieties [PDF]
Fundamenta Mathematicae, 1993 Summary: We prove that a finite atomistic lattice can be represented as a lattice of quasivarieties if and only if it is isomorphic to the lattice of all subsemilattices of a finite semilattice. This settles a conjecture that appeared in the context of an earlier paper by the third author and \textit{V. I.
Adaricheva, K. V. +2 more
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Note on quasivarieties generated by finite pointed abelian groups
Open MathematicsWe prove that a finite pointed abelian group generates a finitely axiomatizable variety that has a finite quasivariety lattice. As a consequence, we obtain that a quasivariety generated by a finite pointed abelian group has a finite basis of quasi ...
Basheyeva Ainur, Lutsak Svetlana
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, 2019 Introduced by C. R. Shallon in 1979, graph algebras establish a useful connection between graph theory and universal algebra. This makes it possible to investigate graph varieties and graph quasivarieties, i.e., classes of graphs described by identities ...
Lehtonen, Erkko, Pöschel, Reinhard
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, 2003 In the paper we consider the notion of hyper-quasi-identities and hyperquasivarieties as a generalization of the concept of quasi-identity and quasivariety invented by A. I.
Graczynska, Ewa, Schweigert, Dietmar
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Constructive Logic with Strong Negation is a Substructural Logic. II [PDF]
, 2018 The goal of this two-part series of papers is to show that constructive logic with strong negation N is definitionally equivalent to a certain axiomatic extension NFL ew of the substructural logic FL ew .
Spinks, M., Veroff, R.
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New-from-old full dualities via axiomatisation
, 2018 We clarify what it means for two full dualities based on the same algebra to be different. Our main theorem gives conditions on two different alter egos of a finite algebra under which, if one yields a full duality, then the other does too.
Davey, Brian A. +2 more
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Admissibility in De Morgan algebras [PDF]
, 2018 Characterizations of admissible quasi-identities, which may be understood as quasi-identities holding in free algebras on countably infinitely many generators, are provided for classes of De Morgan algebras and ...
Metcalfe, George +1 more
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Generating the algebraic theory of $C(X)$: the case of partially ordered compact spaces [PDF]
, 2017 It is known since the late 1960's that the dual of the category of compact Hausdorff spaces and continuous maps is a variety -- not finitary, but bounded by $\aleph_1$.
Hofmann, Dirk +2 more
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On the complexity of quasivariety lattices
Sibirskie Elektronnye Matematicheskie Izvestiya, 2017 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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