Foundation (Asimov)? I don't think it merits a mention here. Or rather, if it should be included, so should many, many more entries.
Likewise, I'm not sure it's on the list, but starship troopers has a kind of mathematics for government (the military dictatorship with citizen-by-merit is provably optimal, not just a random system).
It fictionalized "math" but still fits the generic idea, IMHO.
Where I'm more on the fence are about works that rely strongly on mathematical physics, like Poul Anderson's Tau Zero, or the parts of Pohl's Gateway series that most explicitly refer to black holes. I'd still say those are not "mathematical fiction", but at least it's close.