That would be misleading naming. If Alice is talking to Bob, the attacker in this scenario is a third entity, let's say Claire, who shouts math problems at Bob

That would be misleading naming. If Alice is talking to Bob, the attacker in this scenario is a third entity, let's say Claire, who shouts math problems at Bob until he is sufficiently distracted that he can no longer continue his legitimate conversation(s) with Alice. - as opposed to a regular bandwidth-based DoS where Claire just shouts random words at Bob. Bob's vulnerability here is that he is more easily distracted by certain math problems.