=====Lukasiewicz algebras of order n===== Abbreviation: **LA$_n$** ====Definition==== A \emph{Lukasiewicz algebra of order $n$} is a structure $\mathbf{A}=\langle A,\vee ,0,\wedge ,1,\neg,\sigma_0,\ldots,\sigma_{n-1}\rangle $ such that $\langle A,\vee ,0,\wedge ,1, \neg\rangle $ is a [[De Morgan algebras]] 1. $\sigma_i$ is a lattice homomorphism: $\sigma_i(x\vee y)=\sigma_i(x)\vee\sigma_i(y) \mbox{and} \sigma_i(x\wedge y)=\sigma_i(x)\wedge\sigma_i(y)$ 2. $\sigma_i(x) \vee \neg(\sigma_i(x)) = 1$, $\sigma_i(x) \wedge \neg(\sigma_i(x)) = 0$ 3. $\sigma_i(\sigma_j(x)) = \sigma_j(x)$ for $1 \le j \le n-1$ 4. $\sigma_i(\neg x) = \neg(\sigma_{n-i}(x))$ 5. $\sigma_i(x) \wedge \sigma_j(x) = \sigma_i(x)$ for $i \le j \le n - 1$ 6. $x \vee \sigma_{n-1}(x) = \sigma_{n-1}(x)$, $x \wedge \sigma_1(x) = \sigma_1(x)$ 7. $y \wedge (x \vee \neg(\sigma_i(x)) \vee \sigma_{i+1}(y)) = y$ for $i \ne n - 1$ ==Morphisms== Let $\mathbf{A}$ and $\mathbf{B}$ be Lukasiewicz algebras of order $n$. A morphism from $\mathbf{A}$ to $\mathbf{B}$ is a function $h:A\rightarrow B$ that is a homomorphism: $h(x\vee y)=h(x)\vee h(y)$, $h(\neg x)=\neg h(x)$, $h(\sigma_i(x))=\sigma_i(h(x))$ for $i=0,\ldots,n-1$ ====Examples==== Example 1: ====Basic results==== ====Properties==== ^[[Classtype]] |Variety | ^[[Equational theory]] |decidable | ^[[Quasiequational theory]] | | ^[[First-order theory]] | | ^[[Congruence distributive]] |Yes | ^[[Congruence modular]] |Yes | ^[[Congruence n-permutable]] | | ^[[Congruence regular]] | | ^[[Congruence uniform]] | | ^[[Congruence extension property]] | | ^[[Definable principal congruences]] | | ^[[Equationally def. pr. cong.]] | | ^[[Amalgamation property]] | | ^[[Strong amalgamation property]] | | ^[[Epimorphisms are surjective]] | | ^[[Locally finite]] |yes | ^[[Residual size]] |$n$ | ====Finite members==== $\begin{array}{lr} f(1)= &1\\ f(2)= &\\ f(3)= &\\ f(4)= &\\ f(5)= &\\ f(6)= &\\ f(7)= &\\ f(8)= &\\ f(9)= &\\ f(10)= &\\ \end{array}$ ====Subclasses==== [[Boolean algebras]] ====Superclasses==== [[De Morgan algebras]] ====References==== [(Ln19xx> )]