**This is an old revision of the document!**

## Division ring

### Set

postulate | $\langle X,+,* \rangle \in \mathrm{divisionRing}(X)$ |

context | $\langle X,+,* \rangle \in \mathrm{unitalRing}(X)$ |

context | $\langle X,* \rangle \in \mathrm{group}(X)$ |

postulate | $\exists a,b.\ (a\neq b)$ |

### Ramifications

#### Discussion

A division ring is essentially two *compatible* groups over a set $X$, one of which is necessarily commutative. Compatible in the sense of the distributive laws of a ring, which is asymmetrical with respect to “$+$” and “$*$”.

The second requirement distinguishes the division ring from a unital ring by inverses with respect to the multiplication $*$. The last statement says that $\langle X,+,* \rangle$ must not be the trivial ring.

### Reference

### Parents

#### Subset of