I don't know the legal ins and outs. It sure does seem stupid to me. But the fact is, iPads and iPhones have a significant market share and are otherwise great products. I want to write software for it, but Apple is keeping me for including GPLed mathematics software, and that's frustrating.

As a mathematician and hobbyist iOS developer, it really sucks that so much great mathematics software is GPLed. You can't port Octave, for example, to the iPad as its license is incompatible with Apples terms. I'd love to see this kind of stuff on my iPad. I'd even write it myself! But nope... A few great non-GPLed mathematics packages that have made their way into the iOS ecosystem. There's a Reduce implementation, for example, that looks really nice.

And while I'm rambling (sorry), LaTeX on mobile is just in shambles. I mean, it's in shambles on the desktop, too, but it's nearly impossible to do on mobile. It needs a rewrite. Period. But the mobile dev community has done a really great job getting as far as possible with what we have with LaTeX.