Problem with alignment inside a table and its notes

Question

to explain my problem, please look at this table:

1) I want to bring the red part closer to the middle, so that the three columns are more centered.

2) I want to align the blue part in one vertical line. I tried to use {flalign*}, but this aligns the equations with the column on the top, and not the "Profitability calculation".

This is the code that I use:

\documentclass[12pt]{article}
\usepackage{setspace,amsmath,graphicx,float}
\usepackage[english]{babel}
\usepackage{boldline}
\usepackage{array}
\usepackage[left=3cm,top=3.5cm,right=2.5cm,bottom=2.5cm]{geometry}
\usepackage{times}
\usepackage{threeparttable}
\usepackage[margin=1cm]{caption}
\usepackage{amssymb}
\usepackage{tabularx}

\begin{document}
\begin{table}[H]
\centering
\small
\caption[xxx]{Example calculation for a two-product SSNIP test \citep{QuantTech}.}
\begin{threeparttable}
\begin{tabularx}{\textwidth}{p{20em} >{\centering\arraybackslash}p{8em}  >{\centering\arraybackslash}p{7em}}    
\hlineB{3}
  & Product 1 & Product 2  \\ \hline
Margin & 10\% & 20\% \\
Diversion ratio & 0.29 & 0.5 \\ 
Own-price elasticity of demand & 2 & 4 \\ 
Ratio of prices $p_2 / p_1$ & 1 & 1 \\                       
\hlineB{3}
\end{tabularx}
\begin{tablenotes}
\setlength{\belowdisplayskip}{0pt} \setlength{\belowdisplayshortskip}{0pt}
\setlength{\abovedisplayskip}{0pt} \setlength{\abovedisplayshortskip}{0pt}
\item Profitability calculation:\\
\begin{align*}
\frac{p_1 - c_1}{p_1} \overset{?}{\leqslant} \frac{1}{\eta_{11}(p_1,p_2.\ldots,p_J)} + \frac{p_2 - c_2}{p_2} \frac{p_2}{p_1} DR_{12}, \qquad 0.1 \leqslant \frac{1}{2} + 0.2 \times 1 \times 0.29 = 0.56
 \end{align*}

\begin{align*}
\frac{p_2 - c_2}{p_1} \overset{?}{\leqslant} \frac{1}{\eta_{22}(p_1,p_2.\ldots,p_J)} + \frac{p_1 - c_1}{p_1} \frac{p_1}{p_2} DR_{21}, \qquad 0.2 \leqslant \frac{1}{4} + 0.1 \times 1 \times 0.5 = 0.30
\end{align*}

\end{tablenotes}
\end{threeparttable}
\label{ExampleSSNIP}   
\end{table}
\end{document}

I'm grateful for any help - thanks!

Answer 1

If you really want your table to fill the text width (you shouldn't, unless you're doing two column typesetting), at least don't use \small.

You don't need threeparttable, in this case. Just use \raggedright.

I used newtxtext and newtxmath. You can use mathptmx (but the results are poorer); never ever use times if you have math in your document.

\documentclass[12pt]{article}
\usepackage[left=3cm,top=3.5cm,right=2.5cm,bottom=2.5cm]{geometry}
\usepackage{amsmath}
\usepackage{newtxtext,newtxmath}
\usepackage{booktabs}
\usepackage{natbib}
\usepackage[margin=1cm]{caption}

\begin{document}
\begin{table}

\caption[xxx]{Example calculation for a two-product SSNIP test \citep{QuantTech}.}
\label{ExampleSSNIP}   

\centering

\begin{tabular*}{\textwidth}{
  @{\hspace{.1\textwidth}\extracolsep{\fill}}
  l c c
  @{\hspace{.1\textwidth}}
}
\toprule
                               & Product 1 & Product 2 \\
\midrule
Margin                         & 10\%      & 20\%      \\
Diversion ratio                & 0.29      & 0.5       \\
Own-price elasticity of demand & 2         & 4         \\
Ratio of prices $p_2 / p_1$    & 1         & 1         \\
\bottomrule
\end{tabular*}

\medskip

\raggedright
Profitability calculation:\\[\medskipamount]
$\begin{alignedat}{2}
\frac{p_1 - c_1}{p_1} &\overset{?}{\leqslant} 
  \frac{1}{\eta_{11}(p_1,p_2.\dots,p_J)} + \frac{p_2 - c_2}{p_2} \frac{p_2}{p_1} DR_{12},
  &\qquad& 0.1 \leqslant \frac{1}{2} + 0.2 \times 1 \times 0.29 = 0.56
\\
\frac{p_2 - c_2}{p_1} &\overset{?}{\leqslant} 
  \frac{1}{\eta_{22}(p_1,p_2.\dots,p_J)} + \frac{p_1 - c_1}{p_1} \frac{p_1}{p_2} DR_{21},
  &\qquad& 0.2 \leqslant \frac{1}{4} + 0.1 \times 1 \times 0.5 = 0.30
\end{alignedat}$

\end{table}

\end{document}

Instead of boldrule I used booktabs. Adjust the amount of spacing before the first column and after the last one; but my advice is not to artificially expand tables, particularly if they contain such small amount of columns.

Note that \ldots should be \dots.

Answer 2

Here is a solution, with the flushleft option for tablenotes, and the fleqn environment from nccmath to wrap the align*environment, which has the effect to use the | fleqnoption fromamsmath` locally, for one group of equations.

I also replaced the obsolete times package with newtx, which uses a Times clone (TeX Gyre Termes).

\documentclass[12pt]{article}
\usepackage{setspace,amsmath,graphicx,float}
\usepackage[english]{babel}
\usepackage{boldline}
\usepackage{array}
\usepackage[left=3cm,top=3.5cm,right=2.5cm,bottom=2.5cm]{geometry}
\usepackage{newtxtext, newtxmath}
\usepackage{threeparttable}
\usepackage[margin=1cm]{caption}
\usepackage{amssymb}
\usepackage{tabularx}
\usepackage{nccmath}


 \begin{document}

\begin{table}[H]
  \centering
  \small
  \caption[xxx]{Example calculation for a two-product SSNIP test.}% \citep{QuantTech}
  \begin{threeparttable}
    \begin{tabularx}{\textwidth}{p{20em} >{\centering\arraybackslash}p{8em} >{\centering\arraybackslash}p{7em}}
      \hlineB{3}
                                     & Product 1 & Product 2 \\ \hline
      Margin & 10\,\% & 20\,\% \\
      Diversion ratio & 0.29 & 0.5 \\
      Own-price elasticity of demand & 2 & 4 \\
      Ratio of prices $p_2/p_1 $ & 1 & 1 \\
      \hlineB{3}
    \end{tabularx}
    \begin{tablenotes}[flushleft]
      \setlength{\belowdisplayskip}{0pt} \setlength{\belowdisplayshortskip}{0pt}
      \setlength{\abovedisplayskip}{0pt} \setlength{\abovedisplayshortskip}{0pt}
      \item Profitability calculation:
      \begin{fleqn}[\fontdimen2\font]
        \begin{align*}
          \frac{p_1 - c_1}{p_1} & \overset{?}{\leqslant} \frac{1}{\eta_{11}(p_1,p_2.\ldots,p_J)} + \frac{p_2 - c_2}{p_2} \frac{p_2}{p_1} DR_{12}, & 0.1 & \leqslant \frac{1}{2} + 0.2 × 1 × 0.29 = 0.56 \\%
          \frac{p_2 - c_2}{p_1} & \overset{?}{\leqslant} \frac{1}{\eta_{22}(p_1,p_2.\ldots,p_J)} + \frac{p_1 - c_1}{p_1} \frac{p_1}{p_2} DR_{21}, & 0.2 & \leqslant \frac{1}{4} + 0.1 × 1 × 0.5 = 0.30
        \end{align*}
      \end{fleqn}
    \end{tablenotes}
  \end{threeparttable}
  \label{ExampleSSNIP}
\end{table}

\end{document} 

However I suggest this code, based on tabulary, which looks niver in my opinio:

\documentclass[12pt]{article}
\usepackage{setspace,amsmath,graphicx,float}
\usepackage[english]{babel}
\usepackage{boldline}
\usepackage{array}
\usepackage[left=3cm,top=3.5cm,right=2.5cm,bottom=2.5cm]{geometry}
\usepackage{newtxtext, newtxmath}
\usepackage{threeparttable}
\usepackage[margin=1cm]{caption}
\usepackage{amssymb}
\usepackage{tabularx, tabulary}
\usepackage{nccmath}


 \begin{document}

\begin{table}[H]
  \centering
  \small\setlength\extrarowheight{2pt}
  \caption[xxx]{Example calculation for a two-product SSNIP test.}% \citep{QuantTech}
  \begin{threeparttable}
    \begin{tabulary}{\textwidth}{L>{\centering\arraybackslash}p{8em} >{\centering\arraybackslash}p{8em}@{}}%p{20em} \hlineB{3}
                                     & Product 1 & Product 2 \\ \hlineB{3}
      Margin & 10\,\% & 20\,\% \\
      Diversion ratio & 0.29 & 0.5 \\
      Own-price elasticity of demand & 2 & 4 \\
      Ratio of prices $p_2 / p_1$ & 1 & 1 \\
      \hlineB{3}
    \end{tabulary}
    \begin{tablenotes}[flushleft]\footnotesize
      \setlength{\belowdisplayskip}{0pt} \setlength{\belowdisplayshortskip}{0pt}
      \setlength{\abovedisplayskip}{0pt} \setlength{\abovedisplayshortskip}{0pt}
      \item Profitability calculation:
      \begin{fleqn}[\fontdimen2\font]
        \begin{align*}
          \frac{p_1 - c_1}{p_1} & \overset{?}{\leqslant} \frac{1}{\eta_{11}(p_1,p_2.\ldots,p_J)} + \frac{p_2 - c_2}{p_2} \frac{p_2}{p_1} DR_{12}, & 0.1 & \leqslant \frac{1}{2} + 0.2 \times 1 \times 0.29 = 0.56 \\%
          \frac{p_2 - c_2}{p_1} & \overset{?}{\leqslant} \frac{1}{\eta_{22}(p_1,p_2.\ldots,p_J)} + \frac{p_1 - c_1}{p_1} \frac{p_1}{p_2} DR_{21}, & 0.2 & \leqslant \frac{1}{4} + 0.1 \times 1 \times 0.5 = 0.30
        \end{align*}
      \end{fleqn}
    \end{tablenotes}
  \end{threeparttable}
  \label{ExampleSSNIP}
\end{table}

\end{document}