Surely the FSF has tried to argue this in court.. right?
The RSA patent wasn't on the math. It was on using that math to do something specific.
The RSA patent didn't apply to other uses of that math.
But, as the top-level comment and the original post point out,
> ...any method of manipulating information (i.e an algorithm) can be translated into a Haskell program, every Haskell function is a formula in the Typed Lambda Calculus, and all the variants of the Lambda Calculus are part of mathematics.
The RSA patent doesn't provide source code per se, but it definitely describes a particular algorithm which could be transcribed to lambda calculas.
Yes, but "transcribed to lambda calculus" does not imply that RSA isn't unpatentable any more than "can be translated to Japanese".
Note that you can't patent chemistry, molecules, or forces of nature either. However, no one confuses that with patenting the use of said things for specific applications.
Why do you think that math is different?