q skew derivation QSkewDerivation 2001-10-19 02:18:59 2003-09-20 22:01:28 Definition \usepackage{amssymb} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{graphicx} \usepackage{xypic} Let $(\sigma, \delta)$ be a skew derivation on a ring $R$. Let $q$ be a central \PMlinkname{$(\sigma, \delta)$-constant}{SigmaDeltaConstant}. Suppose further that $\delta\sigma = q \cdot \sigma\delta$. Then we say that $(\sigma, \delta)$ is a $q$-\PMlinkescapetext{{\it skew derivation}}.