A sketch of the lattice of commutative nilpotent semigroup varieties.
A sufficient condition for a variety to have the amalgamation property
A survey of algebra of tournaments.
A survey of minimal clones.
A ternary variety generated by lattices
Abstract clones and operads.
Accessible set functors are universal
It is shown that every concretizable category can be fully embedded into the category of accessible set functors and natural transformations.
Agassiz sum of algebras
Algebraic and graph-theoretic properties of infinite -posets
A -labeled -poset is an (at most) countable set, labeled in the set , equipped with partial orders. The collection of all -labeled -posets is naturally equipped with binary product operations and -ary product operations. Moreover, the -ary product operations give rise to
Algebraic and graph-theoretic properties of infinite n-posets
A Σ-labeled n-poset is an (at most) countable set, labeled in the set Σ, equipped with n partial orders. The collection of all Σ-labeled n-posets is naturally equipped with n binary product operations and nω-ary product operations. Moreover, the ω-ary product operations give rise to nω-power operations. We show that those Σ-labeled n-posets that can be generated from the singletons by the binary and ω-ary product operations form the free algebra on Σ in a variety axiomatizable by an infinite collection...
Algebraic categories whose projectives are explicitly free.
Algebraic duality of constant algebras
Algebras presented by normal identities
Algebras satisfying certain quasiorder identities
Algebras with principal tolerances
Algebras with tolerance extension property in 0
All subvarieties of have finite bases of identities.
All varieties of orthogroups.
Amalgams of free inverse semigroups.
An algebraic version of the Cantor-Bernstein-Schröder theorem
The Cantor-Bernstein-Schröder theorem of the set theory was generalized by Sikorski and Tarski to -complete boolean algebras, and recently by several authors to other algebraic structures. In this paper we expose an abstract version which is applicable to algebras with an underlying lattice structure and such that the central elements of this lattice determine a direct decomposition of the algebra. Necessary and sufficient conditions for the validity of the Cantor-Bernstein-Schröder theorem for...