Last week I told my grad. students that it violates the RN notational system to write anything other than V or viio over a slash, and that even though it is tempting to write something like "ii/IV" in certain situations, you need to use a workaround like bracket notation or a key change. Two of them said that they were taught to write things like "ii/IV" by their undergrad. teachers, which surprised me. I'm curious: Does anyone actually teach this, or have you encountered it?