=====Idempotent semirings with identity===== Abbreviation: **ISRng$_1$** ====Definition==== An \emph{idempotent semiring with identity} is a [[semirings with identity]] $\mathbf{S}=\langle S,\vee,\cdot,1 \rangle $ such that $\vee$ is idempotent: $x\vee x=x$ ==Morphisms== Let $\mathbf{S}$ and $\mathbf{T}$ be idempotent semirings with identity. A morphism from $\mathbf{S}$ to $\mathbf{T}$ is a function $h:S\rightarrow T$ that is a homomorphism: $h(x\vee y)=h(x)\vee h(y)$, $h(x\cdot y)=h(x)\cdot h(y)$, $h(1)=1$ ====Examples==== Example 1: ====Basic results==== ====Properties==== ^[[Classtype]] |variety | ^[[Equational theory]] |decidable | ^[[Quasiequational theory]] | | ^[[First-order theory]] |undecidable | ^[[Locally finite]] |no | ^[[Residual size]] |unbounded | ^[[Congruence distributive]] |no | ^[[Congruence modular]] |no | ^[[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]] | | ====Finite members==== $\begin{array}{lr} f(1)= &1\\ f(2)= &1\\ f(3)= &\\ f(4)= &\\ f(5)= &\\ f(6)= &\\ \end{array}$ ====Subclasses==== [[Idempotent semirings with identity and zero]] ====Superclasses==== [[Idempotent semirings]] [[Semirings with identity]] ====References==== [(Ln19xx> )]