Strange alignment behavior of two numbered equations on the same line

Question

Considering my previous question at this link One or more equations (two-by-two on different rows) with an enumerate to the left and the another on the right, I have a strange alignment behavior of two numbered equations on the same line. In other words there is an overhang between the (0.0-3) and (0.0-4) equations.

How can the problem be corrected?

Here there is the MWE and the relative output:

\documentclass{book}
\usepackage[top=2.5cm,bottom=2.2cm,
            left=3.2cm,right=1.5cm,headsep=10pt,
            a4paper]{geometry}  
\usepackage{mathtools,amssymb}
\usepackage[svgnames, dvipsnames, table, x11names]{xcolor}
\usepackage{pifont}
\usepackage{tabularx} 
\definecolor{ocre}{RGB}{243,102,25} 
\usepackage{lipsum} %%%%%%%%%%% <--------- added 

%----------------------------------------------------------------------------------
%   Change number equations with sections
%----------------------------------------------------------------------------------
\usepackage{chngcntr}
\counterwithin{equation}{section}

\renewcommand{\theequation}{\thesection-\arabic{equation}}
\newcommand{\eqnnumsymbol}{\textcolor{ocre}{\reflectbox{\ding{228}}}}

\makeatletter
\newtagform{bbrackets}% <name>
  [\textbf]% Internal style
  {(}% Left bracket
  {\ifnum\pdfstrcmp{\@currenvir}{equation}=0
     \eqnnumsymbol%
   \else
     \ifnum\pdfstrcmp{\@currenvir}{align}=0
       \eqnnumsymbol%
     \fi
   \fi
   )}% Right bracket
\makeatother
\usetagform{bbrackets}

\begin{document}
\lipsum[5][2-3]

\begin{tabularx}{\textwidth}{@{}XXX@{}}
\begin{equation}
f(x + y) = f(x) + f(y),
\label{eqn:1}
\end{equation} &
\begin{equation}
f(ax) = af(x),\,
x,y\in V, a\in\mathbb{C}
\label{eqn:2}
\end{equation}
\end{tabularx}

\lipsum[6][8-9]

\begin{tabularx}{\textwidth}{@{}XXX@{}}
\begin{equation}
\overline{E}= -\overline \nabla \varphi-\frac{\partial \overline{A}}{\partial t}
\label{eqn:3}
\end{equation} &
\begin{equation}
\overline{B}=\overline \nabla \times\overline{A}
\label{eqn:4}
\end{equation}
\end{tabularx}
\end{document}

Output:

unrelated note you are missing \noindent before the \begin{tabularx} (see the 15pt warnings in the log) and you declare three columns but only use two. — David Carlisle, Sep 07 '19 at 15:51
It is not clear what other behaviour you expect, one equation is taller than the other so it takes more vertical space, you would see the same if it was an image of a tikzpicture or anything else, not just equations. — David Carlisle, Sep 07 '19 at 15:52
@DavidCarlisle I'm absolutely agree with you on \noindent. Into my structure there is no this problem. After I have @{}XXX@{} used directly the code from Stefan Kottwitz's answer https://tex.stackexchange.com/questions/33433/how-to-place-and-number-3-short-equations-in-one-line — Sebastiano, Sep 07 '19 at 15:59
You can fake the height with vphantom: \overline{B}=\overline \nabla \times\overline{A}\vphantom{-\frac{\partial \overline{A}}{\partial t}}. — Marijn, Sep 07 '19 at 16:00
Stefan used XXX as he had three equations per line, so three columns in the table. — David Carlisle, Sep 07 '19 at 16:02

score 1 · Accepted Answer · answered Sep 07 '19 at 16:11

I wouldn't really expect these to be aligned as they have different sizes, however you can get a bit closer if you use m rather than p columns. I use tabular here as tabularx isn't really helping as you know in advance given XX that there will be two equal columns, so you may as well specify that directly.

\documentclass{book}
\usepackage[top=2.5cm,bottom=2.2cm,
            left=3.2cm,right=1.5cm,headsep=10pt,
            a4paper]{geometry}  
\usepackage{mathtools,amssymb}
\usepackage[svgnames, dvipsnames, table, x11names]{xcolor}
\usepackage{pifont}
\usepackage{tabularx} 
\definecolor{ocre}{RGB}{243,102,25} 
\usepackage{lipsum} %%%%%%%%%%% <--------- added 

%----------------------------------------------------------------------------------
%   Change number equations with sections
%----------------------------------------------------------------------------------
\usepackage{chngcntr}
\counterwithin{equation}{section}

\renewcommand{\theequation}{\thesection-\arabic{equation}}
\newcommand{\eqnnumsymbol}{\textcolor{ocre}{\reflectbox{\ding{228}}}}

\makeatletter
\newtagform{bbrackets}% <name>
  [\textbf]% Internal style
  {(}% Left bracket
  {\ifnum\pdfstrcmp{\@currenvir}{equation}=0
     \eqnnumsymbol%
   \else
     \ifnum\pdfstrcmp{\@currenvir}{align}=0
       \eqnnumsymbol%
     \fi
   \fi
   )}% Right bracket
\makeatother
\usetagform{bbrackets}

\begin{document}
\lipsum[5][2-3]

\noindent
\begin{tabular}{@{}*{2}{m{.5\textwidth}@{}}}
\begin{equation}
f(x + y) = f(x) + f(y),
\label{eqn:1}
\end{equation} &
\begin{equation}
f(ax) = af(x),\,
x,y\in V, a\in\mathbb{C}
\label{eqn:2}
\end{equation}
\end{tabular}

\lipsum[6][8-9]

\noindent
\begin{tabular}{@{}*{2}{m{.5\textwidth}@{}}}
\begin{equation}
\overline{E}= -\overline \nabla \varphi-\frac{\partial \overline{A}}{\partial t}
\label{eqn:3}
\end{equation} &
\begin{equation}
\overline{B}=\overline \nabla \times\overline{A}
\label{eqn:4}
\end{equation}
\end{tabular}
\end{document}

score 1 · Answer 2 · answered Sep 07 '19 at 16:14

Thank you very much to @David Carlisle and @Marijn that with your comments I have had another possibility:

\documentclass{book}
\usepackage[top=2.5cm,bottom=2.2cm,
            left=3.2cm,right=1.5cm,headsep=10pt,
            a4paper]{geometry}  
\usepackage{mathtools,amssymb}
\usepackage[svgnames, dvipsnames, table, x11names]{xcolor}
\usepackage{pifont}
\usepackage{tabularx} 
\definecolor{ocre}{RGB}{243,102,25} 
\usepackage{lipsum} %%%%%%%%%%% <--------- added 

%----------------------------------------------------------------------------------
%   Change number equations with sections
%----------------------------------------------------------------------------------
\usepackage{chngcntr}
\counterwithin{equation}{section}

\renewcommand{\theequation}{\thesection-\arabic{equation}}
\newcommand{\eqnnumsymbol}{\textcolor{ocre}{\reflectbox{\ding{228}}}}

\makeatletter
\newtagform{bbrackets}% <name>
  [\textbf]% Internal style
  {(}% Left bracket
  {\ifnum\pdfstrcmp{\@currenvir}{equation}=0
     \eqnnumsymbol%
   \else
     \ifnum\pdfstrcmp{\@currenvir}{align}=0
       \eqnnumsymbol%
     \fi
   \fi
   )}% Right bracket
\makeatother
\usetagform{bbrackets}

\begin{document}
\lipsum[5][2-3]

\begin{tabularx}{\textwidth}{@{}XX@{}}
\begin{equation}
f(x + y) = f(x) + f(y),
\label{eqn:1}
\end{equation} &
\begin{equation}
f(ax) = af(x),\,
x,y\in V, a\in\mathbb{C}
\label{eqn:2}
\end{equation}
\end{tabularx}

\lipsum[6][8-9]

\begin{tabularx}{\textwidth}{@{}XX@{}}
\begin{equation}
\overline{E}= -\overline \nabla \varphi-\frac{\partial \overline{A}}{\partial t}
\label{eqn:3}
\end{equation} &
\begin{equation}
\overline{B}=\overline \nabla \times\overline{A}\vphantom{-\frac{\partial \overline{A}}{\partial t}}
\label{eqn:4}
\end{equation}
\end{tabularx}
\end{document}

Strange alignment behavior of two numbered equations on the same line

2 Answers2