Help with the domain and codomain of the function

[Guest]

I don't know if exist a method in particular to resolve this:
sgn(⌊U(x)⌋)
A sign function.
A floor function.
A unit step function.

[HallsofIvy]

Looks pretty trivial to me. Since we can do any of those things to any number, the domain is, of course, the set of all numbers. Because of the "sign" function the co-domain is {-1, 0, 1}.