Inside-Out versus Outside-In Methods

AR may be enclosed within the larger region. This is the stoichiometric subspace S discussed in Section 8.2.2. 

3 Outside-In Methods AR construction via an outside-in approach is best viewed as the inverse problem of inside-out methods. Whereas inside-out methods are concerned with growing a candidate region at each construction step, outside-in methods seek to reduce the size of the region at each construction step. These methods are subtractive in nature. Outside-in methods compute candidate ARs 

At the time of writing, a sufficiency condition for the AR has still not yet been established. Both inside-out and outside-in methods suffer from uncertainty in construction as a result. A stronger result might be achieved if a construction can be validated using two independent construction methods. Validation could be achieved either theoretically or computationally. 

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