I'm interested in knowing if there is a 0 for strings. A string that would have the following property:

>Addition: x + 0 = 0 + x = x. That is, 0 is an identity element (or neutral element) with respect to addition.

This would be for concatenation of course. I've encountered a problem and this "idea" came to me. I've found other ways to solve my problem, but I'm still wondering if something like a "0" exists for strings.