I'm writing a paper and I use a list to describe some notation in an equation:
blah blah is described by the equation
where x is the state vector, u (is) the input vector, and d (are) the disturbances.
Do I need the "is" and "are" which I put in parentheses? My gut feeling is that I can skip them, but I have a hard time convincing myself.
Edit: I made a small notation edit and added the word "vector" in two places. If this isn't consistent with what you want to write, you can roll the edit back to your original.