The elements in the format were suggested by the contributors: we introduced constraints as we needed them. We are aware that in practice many more constraints could be needed. Here we list some issues that we want to take up in the near (?) future. If you have any ideas on these issues, please let us know.

**Student sectioning constraint.**

In more complicated cases in can be important to do student sectioning, meaning that we define several resource groups and divide a group of students over these groups. For example, we could have parallel groups for the same subject (of the same level) and we can choose how to split the students for better schedules; limits will exist in the minimum and maximum sizes of the groups.-
**Different campuses constraint.**

Maybe students and/or teachers have to travel between different campuses. The solution should be such that this is possible. The precise implementation seems to be different in different cases.