I am reading this wikipedia article about Divergence in statistics and I am a bit confused about the paragraph Geometrical Properties.
In particular I can't understand the following $$ D[\partial_i \partial_j|| \, \cdot \,] = -D[\partial_i || \partial_j]. $$ It probably boils down to some basic calculus lemma, but I can't see it right now.
Any help would be very appreciated!