"Of course, I'm a mathematician, Jacko. I try to avoid putting forward propositions that haven't been properly tested..."

or

Mathematicians don't deal with order. Some kind of order is what they end up with if they're lucky. What they deal with is total chaos.

The part about the paradox is kind of lame and unrealistic. Dobie is very pleased to get a letter from the Director of the Heisenberg Institute that says "It is with the most profound reluctance that we have concluded that the paradox as propounded, in the absence of any of-a-decisive-nature refutation and subject to an in-all-parts-effectively-demonstrable comfirmation, must stand." I guess I think that paradox does play an interesting role in mathematics, but the reality of it is not addressed by this quote or the discussion in the book of the religious paradox "If god can do anything, can he make a rock so heavy that he can't lift it?"

To sum up: The mystery in this one is a bit better than in Mask of Zeus, but from a mathematical point of view it is far inferior.