I like tiddlywiki a lot although setting up is nontrivial. It needs a browser plugin and the wiki needs to be under the downloads directory, otherwise it can't save with modern browsers. Once it works, it's really nice because you can use tags, links etc. You can even visualise the network with the tiddlymap plugin. Can't say about math support.
To be honest though I overestimated my need for a research wiki. I haven't used it nearly as much as I initially thought.