I'm not real sure about a defn. in this problem and need some clarification.
The problem reads..
"The universe is all Real #'s. Let A be the closed interval [0,2] and let B be the closed interval [-1,1]. Find A\B, etc etc."
My question is this: By closed interval, does this mean (for A) that the set is all real #'s between (and including) zero and two? And if not, what does it mean?