Hi, I apologize if this question has been asked before or if it is dumb, but... I'm trying to learn some supersymmetry and have been working through Wess and Bagger. However, I have become confused in chapter 9, when they calculate the propagators of a free chiral superfield theory. My confusion is at the set of equations 9.11: They call the position space Feynman propagator the inverse of (box squared + m squared). It might make sense if it was momentum space and box was the momentum, but elsewhere in the book I believe they are using box to mean the D'Alembert operator. This doesnt seem to make sense and all and I can't figure out what's causing the confusion. Thanks in advance.