Currently, there are no free theorems in Section 7.4. I know that they were badly presented during the lecture, but this can be fixed in the notes. Since we use the operational semantics, presenting free theorems is not such easy and elegant as in the original Wadler's paper (Wadler uses denotational semantics). New ideas and critique regarding presenting free theorems in the operational semantics are welcome in the discussion to this issue.
Currently, there are no free theorems in Section 7.4. I know that they were badly presented during the lecture, but this can be fixed in the notes. Since we use the operational semantics, presenting free theorems is not such easy and elegant as in the original Wadler's paper (Wadler uses denotational semantics). New ideas and critique regarding presenting free theorems in the operational semantics are welcome in the discussion to this issue.