We show that, in a multiparty setting, two nondistillable (bound-entangled) states tensored together can make a distillable state. This is an example of true superadditivity of distillable entanglement. We also show that unlockable bound-entangled states cannot be asymptotically unentangled, providing the first proof that some states are truly bound-entangled in the sense of being both nondisti...

We simplify some conjectures in quantum information theory; the additivity of minimal output entropy, the multiplicativity of maximal output p-norm and the superadditivity of convex closure of output entropy. We construct a unital channel for a given channel so that they share the above additivity properties; we can reduce the conjectures for all channels to those for unital channels.

Coherent information quantifies the achievable rate of reliable quantum transmission through a communication channel. Use correlated states instead factorized ones may result in an increase coherent information, phenomenon known as superadditivity. However, even for simple physical models channels it is rather difficult to detect superadditivity and find advantageous multipartite states. Here w...

The present work is concerned with cooperative games with transferable utility the characteristic function of which may have fuzzy values. Main attention is devoted to notions of superadditivity, convexity, core, and Shapley value. It turns out that the proposed fuzzy counterparts of these notions eliminate difficulties and disappointing features connected with previous approaches.