What is the ruling on medical students agreeing to swap specializations among themselves after the official selection process has been completed, and is this permissible by analogy with waiving race prizes?

It is not permissible to exchange specializations in the manner mentioned. The student does not own the higher specialization; rather, he only has the right to benefit from it. It is not permissible for him to take it and give it to someone else, as this infringes upon the right of those who are entitled to the specialization. This differs from waiving a prize, for the owner of a prize possesses it, whereas the student does not own the specialization. The specialization is like university housing: whoever is entitled to it and desires it may take it; otherwise, it is not permissible for him to take it and give it to someone else, because the specialization is the conferment of a specific right of usufruct to the person himself, and he is not permitted to dispose of it for others.