They are specified in the definition of the operators. Define a new operator '%' that concatenates two numbers together and then show me how in Haskell you would do:

   myfun x y = x ^ 2 % 2 * y * x - y ^ 2

What does it mean to "concatenate two numbers together"?

  55 % 102 would produce 55102

I made it up.

And what does 55.1 % 102 produce? 1e-12 % 3i+12?

And if your answer is "I only need it to work on integers" then don't blame Haskell when I choose to specialise it to Int!

I'm a bad product manager. The % should round the value to a tenth and then concat.

This is a silly example, of course, but the real world isn't short on creativity/silliness.

And for complex numbers?

Precondition: complex numbers are not supported. Unspecified behavior.

OK, then I choose to specialise to the type Double!