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## Bilattices

Abbreviation: Bilat

### Definition

A bilattice is a structure $\mathbf{L}=\langle L,\vee,\wedge,\oplus,\otimes,\neg,rangle$ such that

$\langle L,\vee,\wedge\rangle$ is a lattice,

$\langle L,\oplus,\otimes\rangle$ is a lattice,

$\neg$ is a De Morgan operation for $\vee$, $\wedge$: $\neg(x\vee y)=\neg x\wedge\neg y$, $\neg\neg x=x$ and

$\neg$ commutes with $\oplus$, $\otimes$: $\neg(x\vee y)=\oplus x\wedge\oplus y$, $\neg(x\otimes y)=\neg x\otimes\neg y$.

##### Morphisms

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

$h(x\vee y)=h(x)\vee h(y)$, $h(x\oplus y)=h(x)\oplus h(y)$, $h(x\otimes y)=h(x)\otimes h(y)$, $h(\neg x)=\neg h(x)$

Example 1:

### Properties

Classtype variety undecidable yes yes no unbounded

### Finite members

\$\begin{array}{lr} f(1)= &1
f(2)= &0
f(3)= &0
f(4)= &1
f(5)= &3
f(6)= &32
f(7)= &284
f(8)= &
f(9)= &
f(10)= &