We propose a framework for second-order achievability, called type deviation convergence, that is generally applicable to settings in network information theory, and is especially suitable for lossy source coding and channel coding with cost. We give a second-order achievability bound for lossy source coding with side information at the decoder (Wyner-Ziv problem) that improves upon all known bounds (e.g., Watanabe-Kuzuoka-Tan, Yassaee-Aref-Gohari and Li-Anantharam). We also give second-order achievability bounds for lossy compression where side information may be absent (Heegard-Berger problem) and channels with noncausal state information at the encoder and cost constraint (Gelfand-Pinsker problem with cost) that improve upon previous bounds.

翻译：我们提出了一种称为类型偏差收敛的二阶可达性框架，该框架普遍适用于网络信息论中的各种场景，尤其适用于有损信源编码和带代价的信道编码。针对解码端具有边信息的有损信源编码（Wyner-Ziv问题），我们给出了一个二阶可达界，该界改进了所有已知结果（例如Watanabe-Kuzuoka-Tan、Yassaee-Aref-Gohari以及Li-Anantharam的界）。同时，我们还针对边信息可能缺失的有损压缩（Heegard-Berger问题）以及编码端具有非因果状态信息与代价约束的信道（带代价的Gelfand-Pinsker问题）提出了二阶可达界，这些结果均优于现有界限。