What is the difference between $Z_{+}$ and $Z_{++}$? Is the first all the non-negative integers and the second all the positive integers?
[Math] What does this symbol mean in math? ($Z_+$ and $Z_{++}$)
notation
notation
What is the difference between $Z_{+}$ and $Z_{++}$? Is the first all the non-negative integers and the second all the positive integers?
Best Answer
Let's cover all the bases here:
It might be the case that you are right. In Foundations of Analysis in the Complex Plane (on this page in particular), or as seen below, it agrees with you. $Z^+$ is the set of nonnegative, $Z^{++}$ is the set of positive.
But to be honest, I've never seen that notation before. Conceivably, Z++ is a reference to the object-oriented extension of Z Notation. I don't know much about this either, but it's briefed at wiki.
There is also a specific version of the C++ language that is denoted by Z++ (probably because it's more complicated).
I suppose the thing to take from this is that these symbols could refer to many things, but in particular they refer to whatever the author defined them to be. Hopefully, one of these makes more sense than the others.