definition of a Π-voltage graph, for a given group Π:
 Begin with a digraph G.  (The direction is solely for convenience in notation.)
 A Π-voltage on an arc of G is a label of the arc by an element x of Π. For instance, in the case where Π = ℤn, the label is a number i (mod n).
 A Π-voltage assignment is a function  that labels each arc of G with a Π-voltage.
 A Π-voltage graph is a pair  such that G is a digraph and α is a voltage assignment.
 The voltage group of a voltage graph  is the group Π from which the voltages are assigned.

Note that the voltages of a voltage graph need not satisfy Kirchhoff's voltage law, that the sum of voltages aroundhusky coo. "That's what I think, too."

Bianca.

"Whoa." The phone slips, falls out of my hand, bangs on the concrete floor. I reel it back up by the phone cord. "Bianca. Hi."

"It's been a while. Why haven't you called me?"

"Why? Well. Second year. It's totally brutal. Like boot camp. You have no idea. I've been studying round-the-clock. Nonstop. Twenty-four/seven. I barely have time to _breathe_."

I'm rambling like the Rain Man.

"Hey, I hear you're having this awesome party."

"Yes. Yes, we are. Ricky's idea. It'll be a total scene. I only got invited because I live here."

"Is it okay if I come? Ricky said it would be."

Where is Ricky? I need to strangle him.

"I'm so excited about this party," Bianca says.

"Sweet," I say.

"I'm really excited to see you, too," Bianca says.

Gulp.

"Yeah.