Weak superadditivity of skew information
Liang Cai, Nan Li, Shunlong Luo · Journal of Physics A Mathematical and Theoretical · 2008
We revisit the superadditivity conjecture for skew information which has recently been disproved by Hansen (2007 J. Stat. Phys. 126 643). We establish two weak forms of superadditivity which are conjectured to be optimal. Our results show that in a certain sense the superadditivity is true with '50% off'.