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.