http://en.wikipedia.org/wiki/Double_degree
Double Majors and Double Degrees 的部分提到
Double majors or dual majors consist of two majors attached to a single
degree, as opposed to two separate degrees each with its own field of study.
In some schools, students will earn a double major when the two majors lead
to the same degree name (such as: B.A., B.S., B.F.A.). And they will earn a
double degree when the two majors lead to differently-named degrees (such as:
B.A. and B.S., B.S. and B.F.A.). In general, the number of hours and required
courses are more in a dual-degree program than a double major.
意思就是
数学系双主修化学系，是double major
中文系双主修化学系，是double degrees
是这样子没错吧?