In The Dark Forest, Ye Wenjie passes along the "axioms of cosmic sociology" to Luo Ji while visiting Yang Dong's grave.
Why was Luo Ji at Yang Dong's grave? Did they know each other?
I had forgotten the circumstances of their meeting, and answered the question incorrectly the first time around.
Lou Ji knew Yang Dong from highschool.
The first being stood up to welcome her. "Dr. Ye, is it?"
"You're ... Xiao Luo?"
"Luo Ji. I went to high school with Yang Dong. Why are you ... here?"
—The Dark Forest