2. Scoping:

The HQSet class only sees the following classes: HQSet, HQSysCon, HQSysGen, HQBasis, HQVariable, HQExpression. Therefore, its relations with HQConstraint and HQGenerator must be exploited through getHQSysCon() and getHQSysGen(). This accessibility has the advantage to reduce the connexion between HQSet and HQConstraint. Note here that in the octagon library, we have octagons and constraints (binary and linear) manipulation, but not vectors manipulation.