我需要一些建议来减少下面文档第一行的长度，以使其不超过列的大小：
脚本如下：
\documentclass[10pt,conference,a4paper]{IEEEtran_ICC}
\usepackage{mathtools}
\usepackage{lipsum}
\begin{document}
\begin{align}
& P : \max_{\{a_i(c, \mathbf{z}) \, i \in \mathcal{N}_k \, c \in \mathcal{C}_k \, \mathbf{z} \in \mathcal{Z}_i^k, y_{ij} \, 1 \leq j \leq m \}} \sum_{k} \pi(\mathcal{N}_k) \sum_{i \in \mathcal{N}_k} U_i \left(\sum \nolimits^m_{j=1} l_j \cdot y_{ij} \right) \nonumber \\
& \textrm{Subject to: } \nonumber \\
&\hspace{10mm} \textrm{constraint 1} \label{eq:rate_constraint} \\
&\hspace{10mm} \textrm{constraint 2} \label{eq:schedule_constraint} \\
&\hspace{10mm} \textrm{constraint 3} \label{eq:bitrate_constraint1} \\
\nonumber
\end{align}
\lipsum[1]
\end{document}
答案1
\documentclass[10pt,conference,a4paper]{IEEEtran}
\usepackage{mathtools}
\usepackage{lipsum}
\begin{document}
\begin{align}
& P : \max_{\substack{\{a_i(c, \mathbf{z}) \, i \in \mathcal{N}_k \\
c \in \mathcal{C}_k, \,\mathbf{z} \in \mathcal{Z}_i^k, y_{ij} \\
1 \leq j \leq m \}}}
\sum_{k} \pi(\mathcal{N}_k) \sum_{i \in \mathcal{N}_k} U_i \biggl(\sum^m_{j=1} l_j\cdot y_{ij}\biggr) \nonumber \\
& \textrm{Subject to: } \nonumber \\
&\hspace{10mm} \textrm{constraint 1} \label{eq:rate_constraint} \\
&\hspace{10mm} \textrm{constraint 2} \label{eq:schedule_constraint} \\
&\hspace{10mm} \textrm{constraint 3} \label{eq:bitrate_constraint1} \\
\nonumber
\end{align}
\lipsum[1]
\end{document}