Inner bounds via simultaneous decoding in quantum network information theory

We prove new inner bounds for several multiterminal channels with classical inputs and quantum outputs. Our inner bounds are all proved in the one-shot setting, and are natural analogues of the best classical inner bounds for the respective channels. For some of these channels, similar quantum inner bounds were unknown even in the asymptotic iid setting. We prove our inner bounds by appealing to a new classical-quantum joint typicality lemma proved in a companion paper ("A one-shot quantum joint typicality lemma", Pranab Sen, arXiv:1806.07278). This lemma allows us to lift to the quantum setting many inner bound proofs for classical multiterminal channels that use intersections and unions of typical sets.