Research Article

Theorems on Positive Data: On the Uniqueness of NMF

Figure 2

The figure shows data constructed as in Example 3 and plotted in the same manner as in Figure 1, that is, the dashed triangle is the desired solution, the solid line is the border of the dual of , and the shaded area is the positive span of . It can be seen that the NMF is unique when equals or but not when equals or . In the cases where the NMF is not unique, an alternative solution is shown with a dotted line.
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