I'm working on a series that describes part of an algorithm. I must define a variable f which should assume two different possible values "black" and "white" for different iterations of my algorithm. However, "black" and "white" are not numeric values, so I don't know how to do that in a proper way ...
Here is my try:
I don't know if it's fine to integrates a quantifier with a set... How can I say that f assumes "black" for the first iteration and "white" for the second iteration?
Thank you very much.