A mindmapping standard?

I am having a hard time finding mindmapping apps which support a number of thing.

My idea was to install Freemind/Freeplane and then find a way to edit the mindmaps from Freemind on my Samsung Tab 7+ but can i find anything which supports it? Nope! So I considered the fact freemind might not be the ideal format and maybe I could import and export into freemind for editing on my Ubuntu laptop.

There seems to be no solid universal mindmap format which most mindmapping apps can read and write. It also seems export and import is very hit and miss.

The problem seems to be each one wants to innovate on top of a moving base in a different way and lock their users into using that application. A couple have apps across different platforms. Of course those platforms don’t include Linux making them almost pointless for myself.

What do people use and how do they get around the problem of converting back and forth? It seems crazy that this stuff isn’t described in XML or RDF with SVG for strokes?

Someone tell me something which works on Ubuntu and Android? Please!