# 2-column alignment of equations: left-center

It's a long time since I try to align equations centerly with a prefix on the very left of the page. I was able to develop a basic version of it using IEEEeqnarray of IEEEtran class, but since I'm writing the document to a different journal, I cannot use that enviroment. I tried several combinations of align, aligned, gather, etc. with no success.

The working code developed in IEEEtran class is the following:

\begin{IEEEeqnarray} {LC}
\forall{t} & C_t = F_t+K_t \label{eq:1}\\
\forall{t,i} & C_t = \sum_{t'=1}^t A_i + B_{i,t} \label{eq:2}\\
\end{IEEEeqnarray}


That procuces the image below.

It is worth noticing that neither this code produce the left column to be exactly on the very left since I had to adapt the spacing using several \qquad. How can I reproduce a similar code using standard enviroments?

Moreover, I'd be willing to find a solution to achieve the same result under subequations enviroment, similarly to the image below.

The code of the image is the following

\begin{IEEEeqnarray} {LC}
\forall{t} & C_t = F_t+K_t \label{eq:1}\\
\forall{t,i} & C_t = \sum_{t'=1}^t A_i + B_{i,t} \IEEEyessubnumber \label{eq:2}\\
\end{IEEEeqnarray}


Thank you very much in advance.

• Welcome to TeX.SE.
– Mico
Nov 8, 2018 at 15:55

I propose this hack, based on eqparbox, the fleqn environment from nccmath and a \mysubequations environment:

\documentclass[twocolumn]{ieeetran}
\usepackage{mathtools, nccmath}
\usepackage{lipsum}
\usepackage{eqparbox}
\newcommand{\eqmathbox}[2][M]{\eqmakebox[#1]{$\displaystyle#2$}}

\begin{document}
\lipsum[1]
\begin{IEEEeqnarray} {LC}
\forall{t} & C_t = F_t+K_t \label{eq:1}\\
\forall{t,i} & C_t = \sum_{t'=1}^t A_i + B_{i,t} \label{eq:2}\\
\end{IEEEeqnarray}
\bigskip
\begin{fleqn}[0.6em]
\begin{mysubequations}
\begin{align}
& \forall{t} & & \eqmathbox[E]{C_t = F_t+K_t} \label{eq:1} \\
& \forall{t,i} & & \eqmathbox[E]{C_t = \sum_{t'=1}^t A_i + B_{i,t}} \label{eq:7}\\
& \forall{t,s} & & \eqmathbox[E]{C_t = \sum_{t'=1}^t A_i + B_{i,t} + C + D + E} \label{eq:3}
\end{align}
\end{mysubequations}
\setlength{\abovedisplayskip}{0pt}
\begin{align}
& \forall{t,s} & & \eqmathbox[E]{C_t = \sum_{t'=1}^t A_i + B_{i,t} + C + D + E} \label{eq:4}
\end{align}
\end{fleqn}

\end{document}