A code $C \subseteq \{0, 1, 2\}^n$ of length $n$ is called trifferent if for any three distinct elements of $C$ there exists a coordinate in which they all differ. By $T(n)$ we denote the maximum cardinality of trifferent codes with length. $T(5)=10$ and $T(6)=13$ were recently determined. Here we determine $T(7)=16$, $T(8)=20$, and $T(9)=27$. For the latter case $n=9$ there also exist linear codes attaining the maximum possible cardinality $27$.
翻译:一个长度 $n$ 的码 $C \subseteq \{0, 1, 2\}^n$ 被称为三值不同码,如果对于 $C$ 中任意三个不同的元素,存在一个坐标使得它们在该坐标上的值全不相同。用 $T(n)$ 表示长度为 $n$ 的三值不同码的最大基数。最近已确定 $T(5)=10$ 和 $T(6)=13$。本文我们确定 $T(7)=16$,$T(8)=20$,以及 $T(9)=27$。对于后一种情况 $n=9$,还存在达到最大可能基数 $27$ 的线性码。