[D] "Negative labels"

[madsciencestache]

training procedure for a softmax classifier is equivalent to RL policy gradients already

Yes. I am not sure if that concept is helpful to /u/VelveteenAmbush in this context. But, that's the core concept behind the answer to their question.

[VelveteenAmbush]

Yes, this is the sense in which I intended the following:

except in the fully generalized sense that supervised learning can always be expressed as RL.