This finding motivates the search for algorithms which are computationally tractable and approximate the solution. But there are some analytically tractable cases. NMR spectra are unique, well-resolved, analytically tractable and often highly predictable for small molecules. Subsequent research in this area has focused on the more computationally tractable mildly context-sensitive languages. Before computers, statisticians used methods that were computationally tractable, at the cost of known limitations. This fact leads to an analytically tractable compound distribution. This assumption makes the description of such aerodynamics much more tractable mathematically. It is, however, more mathematically tractable than the Gini Coefficient. Boundaries between tractable and intractable cases have been an active area of research. Steady flows are often more tractable than otherwise similar unsteady flows. The criollo is tractable, intelligent, willing and sensible. The AKC describes the Labrador's temperament as a kind, pleasant, outgoing and tractable nature. We therefore reformulate the model to make it more tractable. Cobham's thesis states that polynomial time is a synonym for "tractable", "feasible", "efficient", or "fast". Our descriptions of Earth's surface must be simpler than reality in order to be tractable.