+% The additive identity element of its argument, which should be
+% an algebraic structure.
+\newcommand*{\zero}[1]{ 0_{{#1}} }
+
+\ifdefined\newglossaryentry
+ \newglossaryentry{zero}{
+ name={\ensuremath{\zero{R}}},
+ description={the additive identity element of $R$},
+ sort=z
+ }
+\fi
+