The active bijection between regions and simplices in supersolvable arrangements of hyperplanes.
The amalgamation property of varieties determined by primitive lattices
The dimension of a variety
Derived varieties were invented by P. Cohn in [4]. Derived varieties of a given type were invented by the authors in [10]. In the paper we deal with the derived variety of a given variety, by a fixed hypersubstitution σ. We introduce the notion of the dimension of a variety as the cardinality κ of the set of all proper derived varieties of V included in V. We examine dimensions of some varieties in the lattice of all varieties of a given type τ. Dimensions of varieties of lattices and all subvarieties...
The facial structure of the finite dimensional latticial cone.
The maximal semigroup of quotients of a finite semilattice.
The semigroup of varieties of weakly associative lattice groups