# What does Delta mean in this case

1. Mar 8, 2008

1. The problem statement, all variables and given/known data

R = { (X,Y) $$\epsilon$$ P(A) x P(A) / (X$$\Delta$$Y) $$\subseteq$$ B}

(X$$\Delta$$Y) $$\subseteq$$ B - what does delta mean?

2. Relevant equations

3. The attempt at a solution

2. Mar 8, 2008

### HallsofIvy

Probably "symmetric difference": A union B \ A intersect B: that is, all points that are in A or B but [/b]not[/b] in both.