sigma, delta constant

If $(\sigma ,\delta )$ is a skew derivation on a ring $R$, then a $(\sigma ,\delta )$-constant is an element $q$ of $R$ such that $\sigma (q)=q$ and $\delta (q)=0$.

Note: If $q$ is a $(\sigma ,\delta )$-constant, then it follows that $\sigma (q\cdot x)=q\cdot \sigma (x)$ and $\delta (q\cdot x)=q\cdot \delta (x)$ for all $x$ in $R$.

Title	sigma, delta constant
Canonical name	SigmaDeltaConstant
Date of creation	2013-03-22 11:49:38
Last modified on	2013-03-22 11:49:38
Owner	antizeus (11)
Last modified by	antizeus (11)
Numerical id	8
Author	antizeus (11)
Entry type	Definition
Classification	msc 16S36