珠詰め限界
$ \left(\begin{array}{l}{n} \\ {0}\end{array}\right)+\left(\begin{array}{l}{n} \\ {1}\end{array}\right)(q-1)+\cdots+\left(\begin{array}{l}{n} \\ {t}\end{array}\right)(q-1)^{t} \le q^{n-k}が成り立つこと
全ての符号はこの式が成り立つ
$ \begin{pmatrix}n \\ r\end{pmatrix}は$ _{n} \mathrm{C}_{r}=\frac{n !}{r !(n-r) !}