For each Z or OCL expression, you must give explicitly the details of

its types in a table as shown in the examples at the end of this

document $($taken from the lectures$).$

If this table containing types information is missing for some question,

than this question won't be marked $($it will get zero$).$

Question $1$

Consider a registration system.

In a given term, when a course is offered, a number of sections are open for it$.$ Students enrolled

in a course are registered in one of its open sections. Each course hs a set of pre$-$requisite courses.

A student cannot enroll in a course unless he passes all its pre$-$requisites.

Based on this description, we define the following types:

$[$STUDENT$,$COURSE,SECTION$]$

The data schema for the registration system is as follows: