Semidistributive lattices

Abbreviation: SdLat

Definition

A semidistributive lattice is a lattice $\mathbf{L}=\langle L,\vee ,\wedge \rangle $ such that

SD$_{\wedge}$: $x\wedge y=x\wedge z\Longrightarrow x\wedge y=x\wedge(y\vee z)$

SD$_{\vee}$: $x\vee y=x\vee z\Longrightarrow x\vee y=x\vee(y\wedge z)$

Morphisms

Let $\mathbf{L}$ and $\mathbf{M}$ be semidistributive lattices. A morphism from $\mathbf{L}$ to $\mathbf{M}$ is a function $h:L\rightarrow M$ that is a homomorphism:

$h(x\vee y)=h(x)\vee h(y)$, $h(x\wedge y)=h(x)\wedge h(y)$

Examples

Example 1: $D[d]=\langle D\cup\{d'\},\vee ,\wedge\rangle$, where $D$ is any distributive lattice and $d$ is an element in it that is split into two elements $d,d'$ using Alan Day's doubling construction.

Basic results

Properties

Finite members

$\begin{array}{lr} f(1)= &1\\ f(2)= &1\\ f(3)= &1\\ f(4)= &2\\ f(5)= &4\\ f(6)= &9\\ f(7)= &22\\ f(8)= &60\\ f(9)= &174\\ f(10)= &534\\ f(11)= &1720\\ f(12)= &5767\\ f(13)= &20013\\ f(14)= &71546\\ \end{array}$

Subclasses

Superclasses

References