我的方程组中没有出现方程编号

Question

我想将以下方程组编号为单个方程，但方程编号未显示。如能提供任何帮助，我将不胜感激。

{\footnotesize
\begin{equation}\label{demomodel}
\begin{array}{lcl}
H'=\underbrace{\mu \frac{(H+F)^i}{K^i+(H+F)^i}h(M_I)}_{\text{new healthy ticks}}-\underbrace{\beta_1 M_I \frac{H}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(d_1+\delta_1) H}_{\text{death}} -\underbrace{\gamma_1 (M_I+M_S) H}_{\text{death due to ticks}}
 -\underbrace{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}_{\text{transition term}},\\
 %next eq
F'=\underbrace{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}_{\text{transition term}}-\underbrace{\beta_1 M_I \frac{F}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(p+d_2+\delta_2) F}_{\text{death}} -\underbrace{\gamma_2 (M_I+M_S) F}_{\text{death due to ticks}}, \\
%next eq
H'_I=\underbrace{\beta_1 M_I \frac{H+F}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(d_3+\delta_3) H_I}_{\text{death}}-\underbrace{\gamma_3 (M_I+M_S)H_I}_{\text{death due to ticks}}, \\
%next eq
M'_I=\underbrace{rM_I\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}_{\text{logistic growth of ticks}}+\underbrace{\beta_2 M_S\frac{H_I}{H+H_I+F}}_{\substack{\text{virus-free ticks to}\\ \text{virus-carrying ticks}}}-\underbrace{\beta_3 M_I \frac{H+F}{H+H_I+F}}_{\substack{\text{virus-carrying ticks lose }\\\text{virus to uninfected host}}}
-\underbrace{\delta_4 M_I}_{\substack{\text{death due}\\ \text{ to virus}}}, \\ 
%next eq
M'_S=\underbrace{rM_S\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}_{\text{logistic growth of ticks}}-\underbrace{\beta_2 M_S \frac{H_I}{H+H_I+F}\nonumber}_{\substack{\text{virus-free ticks to}\\ \text{ virus-carrying ticks}}}+\underbrace{\beta_3 M_I \frac{H+F}{H+H_I+F}}_{\substack{\text{virus-carrying ticks lose}\\\text{virus to uninfected host}}} 
-\underbrace{\delta_5 M_S}_{\substack{\text{death due}\\ \text{to virus}}}. 
\end{array}
\end{equation}
}

Answer 1

您有\nonumber阻止方程编号。您也可以考虑使用\raisetag将其定位在较短的行之一旁。如果您将第一行换行，那么它或多或少适合而不会延伸到边距，

\documentclass{article}

\usepackage{mathtools}

\begin{document}

\noindent X\dotfill X

{\footnotesize
\begin{gather}\label{demomodel}
\hspace*{-1cm}\begin{aligned}
H'&=\underbrace{\mu \frac{(H+F)^i}{K^i+(H+F)^i}h(M_I)}_{\text{new healthy ticks}}-\underbrace{\beta_1 M_I \frac{H}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(d_1+\delta_1) H}_{\text{death}} -\underbrace{\gamma_1 (M_I+M_S) H}_{\text{death due to ticks}}
 -\underbrace{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}_{\text{transition term}},\\
 %next eq
F'&=\underbrace{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}_{\text{transition term}}-\underbrace{\beta_1 M_I \frac{F}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(p+d_2+\delta_2) F}_{\text{death}} -\underbrace{\gamma_2 (M_I+M_S) F}_{\text{death due to ticks}}, \\
%next eq
H'_I&=\underbrace{\beta_1 M_I \frac{H+F}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(d_3+\delta_3) H_I}_{\text{death}}-\underbrace{\gamma_3 (M_I+M_S)H_I}_{\text{death due to ticks}}, \\
%next eq
M'_I&=\underbrace{rM_I\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}_{\text{logistic growth of ticks}}+\underbrace{\beta_2 M_S\frac{H_I}{H+H_I+F}}_{\substack{\text{virus-free ticks to}\\ \text{virus-carrying ticks}}}-\underbrace{\beta_3 M_I \frac{H+F}{H+H_I+F}}_{\substack{\text{virus-carrying ticks lose }\\\text{virus to uninfected host}}}
-\underbrace{\delta_4 M_I}_{\substack{\text{death due}\\ \text{ to virus}}}, \\ 
%next eq
M'_S&=\underbrace{rM_S\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}_{\text{logistic growth of ticks}}-\underbrace{\beta_2 M_S \frac{H_I}{H+H_I+F}}_{\substack{\text{virus-free ticks to}\\ \text{ virus-carrying ticks}}}+\underbrace{\beta_3 M_I \frac{H+F}{H+H_I+F}}_{\substack{\text{virus-carrying ticks lose}\\\text{virus to uninfected host}}} 
-\underbrace{\delta_5 M_S}_{\substack{\text{death due}\\ \text{to virus}}}. 
\end{aligned}\hspace*{-1cm}
\raisetag{110pt}
\end{gather}
}

\bigskip


{\footnotesize
\begin{gather}\label{demomodel}
\begin{aligned}
H'&=\begin{multlined}[t]\underbrace{\mu \frac{(H+F)^i}{K^i+(H+F)^i}h(M_I)}_{\text{new healthy ticks}}-\underbrace{\beta_1 M_I \frac{H}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(d_1+\delta_1) H}_{\text{death}} -\underbrace{\gamma_1 (M_I+M_S) H}_{\text{death due to ticks}}
 \\{}-\underbrace{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}_{\text{transition term}},\end{multlined}\\
 %next eq
F'&=\underbrace{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}_{\text{transition term}}-\underbrace{\beta_1 M_I \frac{F}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(p+d_2+\delta_2) F}_{\text{death}} -\underbrace{\gamma_2 (M_I+M_S) F}_{\text{death due to ticks}}, \\
%next eq
H'_I&=\underbrace{\beta_1 M_I \frac{H+F}{H+H_I+F}}_{\text{infected ticks}}-\underbrace{(d_3+\delta_3) H_I}_{\text{death}}-\underbrace{\gamma_3 (M_I+M_S)H_I}_{\text{death due to ticks}}, \\
%next eq
M'_I&=\underbrace{rM_I\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}_{\text{logistic growth of ticks}}+\underbrace{\beta_2 M_S\frac{H_I}{H+H_I+F}}_{\substack{\text{virus-free ticks to}\\ \text{virus-carrying ticks}}}-\underbrace{\beta_3 M_I \frac{H+F}{H+H_I+F}}_{\substack{\text{virus-carrying ticks lose }\\\text{virus to uninfected host}}}
-\underbrace{\delta_4 M_I}_{\substack{\text{death due}\\ \text{ to virus}}}, \\ 
%next eq
M'_S&=\underbrace{rM_S\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}_{\text{logistic growth of ticks}}-\underbrace{\beta_2 M_S \frac{H_I}{H+H_I+F}}_{\substack{\text{virus-free ticks to}\\ \text{ virus-carrying ticks}}}+\underbrace{\beta_3 M_I \frac{H+F}{H+H_I+F}}_{\substack{\text{virus-carrying ticks lose}\\\text{virus to uninfected host}}} 
-\underbrace{\delta_5 M_S}_{\substack{\text{death due}\\ \text{to virus}}}. 
\end{aligned}
\raisetag{100pt}
\end{gather}
}
\end{document}

Answer 2

这个答案中采用的基本方法与 David Carlisle 的非常相似回答，即摆脱了\nonumber指令并array用环境替换split环境。

这里给出的答案与戴维的答案不同，因为它（a）不使用\footnotesize，使用三个额外的换行符，并使用（印刷）支柱将指令的第二个参数\underbrace放在相同的高度，从而（希望）让你的文章的读者更有可能想要阅读所有额外的解释材料。

\documentclass{article}
\usepackage{mathtools,mleftright}
\mleftright
% define 3 typographic struts:
\newcommand\strutA{\vphantom{\frac{(H)^i}{(F)^i}}}
\newcommand\strutB{\vphantom{\left(\frac{F}{F}\right)}}
\newcommand\strutC{\vphantom{\frac{H}{H_I}}}

\begin{document}
\hrule % just to illustrate width of textblock

\begin{equation}\label{demomodel}
\addtolength\jot{4pt} % for a more open "look"
\begin{split}
H'&={\underbrace{\mu \frac{(H+F)^i}{K^i+(H+F)^i}h(M_I)}_{\text{new healthy ticks}}}
   -{\underbrace{\beta_1 M_I \frac{H}{H+H_I+F}\strutA}_{\text{infected ticks}}}
   -{\underbrace{(d_1+\delta_1) H\strutA}_{\text{death}}} \\[-2pt]
   &\qquad
   -{\underbrace{\gamma_1 (M_I+M_S) H\strutB}_{\text{death due to ticks}}} 
   -{\underbrace{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}_{\text{transition term\vphantom{d}}}} \\
%next eq
F'&={\underbrace{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}_{\text{transition term}}}
   -{\underbrace{\beta_1 M_I \frac{F}{H+H_I+F}\strutB}_{\text{infected ticks}}}
   -{\underbrace{(p+d_2+\delta_2) F\strutB}_{\text{death}}} \\[-2pt]
   &\qquad
   -{\underbrace{\gamma_2 (M_I+M_S) F}_{\text{death due to ticks}}} \\
%next eq
H'_I &={\underbrace{\beta_1 M_I \frac{H+F}{H+H_I+F}}_{\text{infected ticks}}}
   -{\underbrace{(d_3+\delta_3) H_I\strutC}_{\text{death}}}
   -{\underbrace{\gamma_3 (M_I+M_S)H_I\strutC}_{\text{death due to ticks}}} \\
%next eq
M'_I &={\underbrace{rM_I\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}_{\text{logistic growth of ticks}}}
   +{\underbrace{\beta_2 M_S\frac{H_I}{H+H_I+F}\strutB}_{\substack{\text{virus-free ticks to\vphantom{g}}\\ \text{virus-carrying ticks}}}}\\[-2pt]
   &\qquad
   -{\underbrace{\beta_3 M_I \frac{H+F}{H+H_I+F}}_{\substack{\text{virus-carrying ticks lose}\\ \text{virus to uninfected host}}}}
   -{\underbrace{\delta_4 M_I\strutC}_{\substack{\text{death due\vphantom{g}}\\ \text{to virus\vphantom{f}}}}} \\ 
%next eq
M'_S &={\underbrace{rM_S\left(1-\frac{M_I+M_S}{\alpha(H+H_I+F)}\right)}_{\text{logistic growth of ticks}}}
   -{\underbrace{\beta_2 M_S \frac{H_I}{H+H_I+F}\strutB}_{\substack{\text{virus-free ticks to\vphantom{g}}\\ \text{ virus-carrying ticks}}}}\\[-2pt]
   &\qquad
   +{\underbrace{\beta_3 M_I \frac{H+F}{H+H_I+F}}_{\substack{\text{virus-carrying ticks lose}\\ \text{virus to uninfected host}}}} \,
   -{\underbrace{\delta_5 M_S\strutC}_{\substack{\text{death due\vphantom{g}}\\ \text{to virus}}}}
\end{split} 
\end{equation}

\end{document}

Answer 3

即使有，线条仍然太长\footnotesize。

这是一种使用 ; 在方程式之间分割较长方程式的方法multlined，我添加了一些垂直空间以更好地将它们分开。您可以选择\small或\footnotesize; 或甚至两者都不选择。

请注意，在显示之前使用\footnotesize或会在周围材料中产生不良的垂直间距，因此我选择使用带有技巧的显示内部的尺寸更改命令。\small\mbox

我还引入了一个\ubracetext简化输入的命令。第二个参数在处拆分\\，每个项目都\text自动用 换行。

\documentclass{article}
\usepackage{amsmath,mathtools}

\newcommand{\ubracetext}[2]{{\underbrace{#1}_{\ubracetextprocess{#2}}}}

\ExplSyntaxOn
\NewDocumentCommand{\ubracetextprocess}{m}
 {
  \seq_set_split:Nnn \l_tmpa_seq { \\ } { #1 }
  \seq_set_map:NNn \l_tmpb_seq \l_tmpa_seq { \text{\vphantom{Ay}##1} }
  \substack{ \seq_use:Nn \l_tmpb_seq { \\ } }
 }
\ExplSyntaxOff

\begin{document}

\begin{equation}\label{demomodel}
\mbox{%
  %\footnotesize
  \small
  $\begin{aligned}
H'
&= \begin{multlined}[t]
   \ubracetext{\mu \frac{(H+F)^i}{K^i+(H+F)^i}h(M_I)}{new healthy ticks}
  -\ubracetext{\beta_1 M_I \frac{H}{H+H_I+F}}{infected ticks}
  -\ubracetext{(d_1+\delta_1) H}{death}
  \\
  -\ubracetext{\gamma_1 (M_I+M_S) H}{death due to ticks}
  -\ubracetext{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}{transition term},
  \end{multlined}
\\[2ex]
F'
&= \begin{multlined}[t]
   \ubracetext{H\left(\sigma_1-\sigma_2 \left(\frac{F}{H+F}\right)\right)}{transition term}
  -\ubracetext{\beta_1 M_I \frac{F}{H+H_I+F}}{infected ticks}
  \\
  -\ubracetext{(p+d_2+\delta_2) F}{death}
  -\ubracetext{\gamma_2 (M_I+M_S) F}{death due to ticks},
  \end{multlined}
\\[2ex]
H'_I
&= \ubracetext{\beta_1 M_I \frac{H+F}{H+H_I+F}}{infected ticks}
  -\ubracetext{(d_3+\delta_3) H_I}{death}
  -\ubracetext{\gamma_3 (M_I+M_S)H_I}{death due to ticks},
\\[2ex]
M'_I
&= \begin{multlined}[t]
   \ubracetext{rM_I\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}{logistic growth of ticks}
  +\ubracetext{\beta_2 M_S\frac{H_I}{H+H_I+F}}{virus-free ticks to \\ virus-carrying ticks}
  \\
  -\ubracetext{\beta_3 M_I \frac{H+F}{H+H_I+F}}{virus-carrying ticks lose \\ virus to uninfected host}
  -\ubracetext{\delta_4 M_I}{death due \\ to virus},
  \end{multlined}
\\[2ex]
M'_S
&= \begin{multlined}[t]
   \ubracetext{rM_S\left(1-\frac{M_I+M_S}{\alpha (H+H_I+F)}\right)}{logistic growth of ticks}
  -\ubracetext{\beta_2 M_S \frac{H_I}{H+H_I+F}}{virus-free ticks to \\ virus-carrying ticks}
  \\
  +\ubracetext{\beta_3 M_I \frac{H+F}{H+H_I+F}}{virus-carrying ticks lose \\ virus to uninfected host} 
  -\ubracetext{\delta_5 M_S}{death due \\ to virus}. 
  \end{multlined}
\end{aligned}$}% end of the \mbox
\end{equation}

\end{document}