* libraries assume a naive equality works for all types. Holds in a world of infinte precision and lossless operations, but never holds for approximations.

* our propagation of universal error values is incomplete, and usually missing from complex algorithms. In other words `Either String` Monad does not work: we want collections of error values just like we have collections of inputs.

Personally I will be overjoyed when our community finally gets the better type class library for approximated types.

Would You agree to review a teaser if I post it here?

Yes, please. I'm curious whether there is a single abstraction that can describe both finite precision with variable errors as well as potentially infinite precision with known errors. Olaf