I noticed early on that the problem was ambiguous in this respect. Fortunately, for the point made, about the gains from cooperation and defection, it doesn’t matter: all you need is that it’s possible to share in larger gains by cooperating, unless someone defects, and the professor’s reaction to what happened.
No, I don’t think that’s what he means. There’s an ambiguity in what is meant by “joint bid” in:
If seven people bid $0.01, does the prof take $0.01 for his $20, or does he take $0.07?
I noticed early on that the problem was ambiguous in this respect. Fortunately, for the point made, about the gains from cooperation and defection, it doesn’t matter: all you need is that it’s possible to share in larger gains by cooperating, unless someone defects, and the professor’s reaction to what happened.