=====Neofileds===== Abbreviation: **Nfld** ====Definition==== A \emph{neofield} is a structure $\mathbf{F}=\langle F,+,\backslash,/,0,\cdot,1,^{-1}\rangle $ of type $\langle 2,2,2,0,2,0,1\rangle $ such that $\langle F,+,\backslash,/,0\rangle $ is a [[loop]] $\langle F-\{0\},\cdot,1,^{-1}\rangle$ is a [[group]] $\cdot$ distributes over $+$: $x\cdot(y+z)=x\cdot y+x\cdot z$ and $(x+y)\cdot z=x\cdot z+y\cdot z$ ==Morphisms== Let $\mathbf{F}$ and $\mathbf{K}$ be neofields. A morphism from $\mathbf{F}$ to $\mathbf{K}$ is a function $h:F\to K$ that is a homomorphism: $h(x+y)=h(x)+h(y)$, $h(x\backslash y)=h(x)\backslash h(y)$, $h(x/y)=h(x)/h(y)$, $h(0)=0$, $h(x\cdot y)=h(x)\cdot h(y)$, $h(1)=1$ ====Examples==== Example 1: ====Basic results==== ====Properties==== ^[[Classtype]] | | ^[[Equational theory]] | | ^[[Quasiequational theory]] | | ^[[First-order theory]] | | ^[[Locally finite]] | | ^[[Residual size]] | | ^[[Congruence distributive]] | | ^[[Congruence modular]] | | ^[[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==== $\begin{array}{lr} f(1)= &1\\ f(2)= &\\ f(3)= &\\ f(4)= &\\ f(5)= &\\ f(6)= &\\ \end{array}$ ====Subclasses==== [[Division rings]] ====Superclasses==== [[Left neofields]] ====References==== Paige L.J., Neofields, Duke Math. J. 16 (1949), 39--60. [(Ln19xx> )]