Well, it is simply

> coerce :: a -> b
> coerce _ = undefined

so coerce is simply empty function. But still, it is possible to write a function of type (a->b).
Well, possibly I didn't write anything particularly new, but please excuse me for I'm still in
sort of a shock after I've discovered it.

Yet this function reminds me how little I know so I have a question for you.
I didn't took any lectures in Category Theory (for I'm still just a student, and I won't for there are none in my institute),
but are there any good (e)books you would recommend for a (future) computer scientist?

Regards

Christopher Skrzętnicki