=====Stone algebras===== Abbreviation: **StAlg** ====Definition==== A \emph{Stone algebra} is a [[distributive p-algebra]] $\mathbf{L}=\langle L,\vee ,0,\wedge ,1,^*\rangle $ such that $(x^*)^*\vee x^* =1$, $0^*=1$ ==Morphisms== Let $\mathbf{L}$ and $\mathbf{M}$ be Stone algebras. A morphism from $\mathbf{L}$ to $\mathbf{M}$ is a function $h:L\rightarrow M$ that is a homomorphism: $h(x\vee y)=h(x)\vee h(y)$, $h(x\wedge y)=h(x)\wedge h(y)$, $h(0)=0 $, $h(1)=1$, $h(x^*)=h(x)^*$ ====Examples==== Example 1: ====Basic results==== ====Properties==== ^[[Equational theory]] |decidable | ^[[Quasiequational theory]] | | ^[[First-order theory]] | | ^[[Congruence distributive]] |yes | ^[[Congruence modular]] |yes | ^[[Congruence n-permutable]] | | ^[[Congruence regular]] | | ^[[Congruence uniform]] | | ^[[Congruence extension property]] |yes | ^[[Definable principal congruences]] | | ^[[Equationally def. pr. cong.]] | | ^[[Amalgamation property]] |yes | ^[[Strong amalgamation property]] | | ^[[Epimorphisms are surjective]] | | ^[[Locally finite]] | | ^[[Residual size]] | | ====Finite members==== $\begin{array}{lr} f(1)= &1\\ f(2)= &1\\ f(3)= &1\\ f(4)= &2\\ f(5)= &2\\ f(6)= &4\\ f(7)= &5\\ f(8)= &10\\ f(9)= &16\\ f(10)= &28\\ \end{array}$ ====Subclasses==== [[Double Stone algebras]] ====Superclasses==== [[Distributive p-algebras]] ====References==== [(Ln19xx> )]