 A main advantage is that we work directly in the full model space rather than in a preconditioned model space, (1) avoiding biased uncertainty analysis and (2) splitting the analysis into the resolved and unresolved tomography spaces.
<coherence>  A main advantage is that we work directly in the full model space rather than in a preconditioned model space, (1) avoiding biased uncertainty analysis and (2) splitting the analysis into the resolved and unresolved tomography spaces.
 A main advantage is that we work directly in the full model space rather than in a preconditioned model space, we split the analysis into the resolved and unresolved tomography spaces.