In this paper we investigate known Singleton-like bounds in the Lee metric and characterize optimal codes, which turn out to be very few. We then focus on Plotkin-like bounds in the Lee metric and present a new bound that extends and refines a previously known, and out-performs it in the case of non-free codes. We then compute the density of optimal codes with regard to the new bound. Finally we fill a gap in the characterization of Lee-equidistant codes.

翻译：在本文中,我们调查了 Lee 标准中已知的Singleton 类似界限,并给最佳代码定性,这些代码后来变得很少。然后我们把重点放在李标准中类似Plotkin 的界限上,提出一个新的界限,扩展和完善一个以前已知的界限,在非免费代码中,该界限优于该界限。然后我们计算出新约束中最佳代码的密度。最后,我们填补了对 Lee-equistant 代码定性的空白。