There is a growing interest in models that extend beyond Shannon's classical transmission scheme, renowned for its channel capacity formula $C$. One such promising direction is message identification via channels, introduced by Ahlswede and Dueck. Unlike in Shannon's classical model, where the receiver aims to determine which message was sent from a set of $M$ messages, message identification focuses solely on discerning whether a specific message $m$ was transmitted. The encoder can operate deterministically or through randomization, with substantial advantages observed particularly in the latter approach. While Shannon's model allows transmission of $M = 2^{nC}$ messages, Ahlswede and Dueck's model facilitates the identification of $M = 2^{2^{nC}}$ messages, exhibiting a double exponential growth in block length. In their seminal paper, Ahlswede and Dueck established the achievability and introduced a "soft" converse bound. Subsequent works have further refined this, culminating in a strong converse bound, applicable under specific conditions. Watanabe's contributions have notably enhanced the applicability of the converse bound. The aim of this survey is multifaceted: to grasp the formalism and proof techniques outlined in the aforementioned works, analyze Watanabe's converse, trace the evolution from earlier converses to Watanabe's, emphasizing key similarities and differences that underpin the enhancements. Furthermore, we explore the converse proof for message identification with feedback, also pioneered by Ahlswede and Dueck. By elucidating how their approaches were inspired by preceding proofs, we provide a comprehensive overview. This overview paper seeks to offer readers insights into diverse converse techniques for message identification, with a focal point on the seminal works of Hayashi, Watanabe, and, in the context of feedback, Ahlswede and Dueck.

翻译：近年来，人们对超越香农经典传输模型的方案兴趣日益增长，该模型以其信道容量公式 $C$ 而闻名。其中一个有前景的方向是由 Ahlswede 和 Dueck 提出的基于信道的消息识别模型。与香农经典模型不同——在经典模型中接收者旨在从 $M$ 个消息集合中确定发送了哪个消息——消息识别仅关注判别特定消息 $m$ 是否被传输。编码器可以确定性地或通过随机化方式操作，特别是在后一种方法中观察到显著优势。虽然香农模型允许传输 $M = 2^{nC}$ 个消息，但 Ahlswede 和 Dueck 的模型能够识别 $M = 2^{2^{nC}}$ 个消息，呈现出块长度的双指数增长。在其开创性论文中，Ahlswede 和 Dueck 建立了可达性并引入了一个“软”逆定理界。后续研究进一步改进该界，最终在特定条件下得到了强逆定理界。Watanabe 的贡献显著增强了逆定理界的适用性。本综述的目标是多方面的：理解上述工作中概述的形式化体系与证明技术，分析 Watanabe 的逆定理，追溯从早期逆定理到 Watanabe 逆定理的演进过程，强调支撑这些改进的关键相似点与差异。此外，我们探讨了由 Ahlswede 和 Dueck 率先提出的带反馈消息识别的逆定理证明。通过阐明他们的方法如何受先前证明的启发，我们提供了一个全面的概述。本综述论文旨在让读者深入了解消息识别中的多种逆定理技术，重点关注 Hayashi、Watanabe 的开创性工作，以及在反馈场景下 Ahlswede 和 Dueck 的贡献。