Several communication models that are of relevance in practice are asymmetric in the way they act on the transmitted "objects". Examples include channels in which the amplitudes of the transmitted pulses can only be decreased, channels in which the symbols can only be deleted, channels in which non-zero symbols can only be shifted to the right (e.g., timing channels), subspace channels in which the dimension of the transmitted vector space can only be reduced, unordered storage channels in which the cardinality of the stored (multi)set can only be reduced, etc. We introduce a formal definition of an asymmetric channel as a channel whose action induces a partial order on the set of all possible inputs, and show that this definition captures all the above examples. Such a general approach allows one to treat all these different models in a unified way, and to obtain a characterization of optimal error-detecting codes for many interesting asymmetric channels by using Sperner theory.

翻译：在实际中具有相关性的若干通信模式在对传输的“对象”采取行动的方式上是不对称的。例子包括:传输脉冲的振幅只能减少的渠道、符号只能删除的渠道、非零符号只能转移到右边的渠道(例如计时频道)、传播矢量空间的尺寸只能缩小的子空间渠道、储存器的基点只能缩小的未定序存储渠道等。我们引入了不对称渠道的正式定义,作为其行动导致所有可能的投入部分排序的渠道,并表明这一定义捕捉了所有上述例子。这种一般性方法允许人们以统一的方式对待所有这些不同的模型,并通过使用Sperner理论对许多有趣的不对称渠道的最佳错误探测代码进行定性。