“Sol sneered. “The Unabomber was a mathematician.”
“What Ted Kaczynski did can barely be called math,” David said.  “Boundary conditions! Totally irrelevant.”
“He had a PhD.”
“From the University of Michigan. I don’t know if that even counts. And don’t think I don’t know that it was his brother who turned him in.”
Sol looked at him closely. “Whose name was David. That’s your name, right?”
“I would never turn you in.”
Sol shrugged. “Of course not,” he said and drove on.”