在 IEEE 中，许多最近的期刊也以 HTML 格式提供。pdf 版本的一个优点是 tex 代码很容易获得，大方程式可以直接从 tex 源中获取。下面分享了一个快照。但是当我尝试在 tex 文件中使用下面示例 1 中给出的原样代码时，它给出了以下错误
! Undefined control sequence.
l.46 $$\eqalignno
{
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.
使用下面给出的示例 2 时出现类似错误
代码：
示例 1
$$\eqalignno{{\mbi x}(t + 1) = &\, {\mbi\Phi} (t){\mbi x}(t) + {\mbi{\mbi \Gamma}} (t){\mbi w}(t)&{\hbox{(1)}} \cr {\mmb z}(t) =&\, {\mbi H}(t) {\mbi x}(t) + {\mbi \nu}(t)&{\hbox{(2)}}}$$
示例 2
$$\displaylines{{\mbi y}(t) = \xi_1 (t){\mmb z}(t) + \xi _2 (t){\mmb z}(t - 1) + \xi _3 (t){\mbi y}(t - 1)\hfill\cr\hfill + (1 - \xi _1 (t) - \xi _2 (t) - \xi _3 (t)){\mbi \nu}(t).\quad{\hbox{(6)}}}$$
请帮我修复这个错误
答案1
\equalignno是纯 TeX，因此未在 LaTeX 中定义。如果您使用纯 TeX，它应该可以工作。
\font\bolditalmath=cmmib10
\newfam\zz
\textfont\zz=\bolditalmath
\def\mbi{\fam\zz}
\let\mmb=\mbi %??
Test:
$$\eqalignno{{\mbi x}(t + 1) = &\, {\mbi\Phi} (t){\mbi x}(t) + {\mbi{\mbi
\Gamma}} (t){\mbi w}(t)&{\hbox{(1)}} \cr {\mmb z}(t) =&\, {\mbi H}(t)
{\mbi x}(t) + {\mbi \nu}(t)&{\hbox{(2)}}}$$
\bye