topological ring

A ring $R$ which is a topological space is called a topological ring if the addition, multiplication, and the additive inverse functions are continuous functions from $R\times R$ to $R$.

A topological division ring is a topological ring such that the multiplicative inverse function is continuous away from $0$. A topological field is a topological division ring that is a field.

Remark. It is easy to see that if $R$ contains the multiplicative identity $1$, then $R$ is a topological ring iff addition and multiplication are continuous. This is true because the additive inverse of an element can be written as the product of the element and $-1$. However, if $R$ does not contain $1$, it is necessary to impose the continuity condition on the additive inverse operation.

Title	topological ring
Canonical name	TopologicalRing
Date of creation	2013-03-22 12:45:59
Last modified on	2013-03-22 12:45:59
Owner	djao (24)
Last modified by	djao (24)
Numerical id	6
Author	djao (24)
Entry type	Definition
Classification	msc 12J99
Classification	msc 13J99
Classification	msc 54H13
Related topic	TopologicalGroup
Related topic	TopologicalVectorSpace
Defines	topological field
Defines	topological division ring