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This follows from the ideas in the post http://article.gmane.org/gmane.science.nmr.relax.devel/5858.

These tests cover all parameter value combinations which result in no exchange:

- dw = 0.0,
- pA = 1.0,
- kex = 0.0,
- dw = 0.0 and pA = 1.0,
- dw = 0.0 and kex = 0.0,
- pA = 1.0 and kex = 0.0,
- dw = 0.0, pA = 1.0, and kex = 0.0.

Such tests should be replicated for all dispersion models.