+%
+% Standard calculus operations.
+%
+\ifx\havemjocalculus\undefined
+\def\havemjocalculus{1}
+
+
% The gradient of its argument, which should be a function from R^n to
% R (or maybe some other field).
\newcommand*{\gradient}[1]{ \nabla{{#1}} }
+
+
+\fi