When using the MediaWiki MathJax extension, it's trivial to create new commands with \newcommand. From the MathJax documentation: You can use the \def, \newcommand, \renewcommand, ...
How do I take my TiddlyWiki pages and add them to a MediaWiki? Other than manually copying and pasting, of course.
Is it possible in MediaWiki markup to repeat table column headings automatically?