Updates To Union Operator in IEGenLib

[tpops]

Union operation on two sets creates a new set with disjunct of conjunctions from both sets. For instance:

S3 := S1 U S2
S3 { Conjs(S1), Conjs(S2)}

There are is a special case however when the Union is not necessarily a disjunct of conjunction. This is a case where the Convex Hull of both sets is equal to the union. In this case, a single conjunction can be used to describe the Union.

In a case where the union is non-convex, we revert back to a union as a disjunction of conjunctions.

What needs to be implemented

• Convex Hull- Use Omega's implementation.
• Difference In IEGenLib
• Union
• Unit Tests

[tpops]

Marking this as invalid as there is no need to modify the Union Operator, codegen can directly support Union and Omega Integration was expanded to take unions as well.