Natural dualities for varieties of distributive lattices with a quantifier
Nd-solid varieties
A non-deterministic hypersubstitution maps any operation symbol of a tree language of type τ to a set of trees of the same type, i.e. to a tree language. Non-deterministic hypersubstitutions can be extended to mappings which map tree languages to tree languages preserving the arities. We define the application of a non-deterministic hypersubstitution to an algebra of type τ and obtain a class of derived algebras. Non-deterministic hypersubstitutions can also be applied to equations of type τ. Formally,...
Nonfinitely based pseudovarieties and inherently nonfinitely based varieties.
Nonfree projectives in products of group varieties
Non-idempotent left symmetric left distributive groupoids
Subdirectly irreducible non-idempotent groupoids satisfying and are studied.
Non-modular congruence lattices of Rees matrix semigroups
Normal functors and strong protomodularity.
Normalization of -algebras
We consider algebras determined by all normal identities of -algebras, i.e. algebras of many-valued logics. For such algebras, we present a representation based on a normalization of a sectionally involutioned lattice, i.e. a -lattice, and another one based on a normalization of a lattice-ordered group.
Not every equational class of infinitary algebras contains a simple algebra
Note on a representation of universal algebras as subdirect powers
Notes on congruence implication