# newtxmath and breqn problem: Viewing capital Greek math incorrectly

I am writing a document with too many long equations and I adopted the use of breqn package for its simplicity in writing such long equations when alignment is not a big restriction. The problem is when I use newtxmath I can not get correct Greek math capitals. If I use Computer Modern, the problem disappears.

Here is my MWE which shows the problem:

\documentclass[a4paper,oneside,12pt]{book}
\usepackage{lmodern}
\usepackage{newtxtext}
\usepackage[scaled=0.92]{helvet}
\usepackage{textcomp}
\usepackage{amsmath}
\usepackage[cmintegrals,bigdelims]{newtxmath}
%\usepackage{flexisym}
%\usepackage{breqn}

\begin{document}
Some alternative text goes here.
%
$$\label{eqdsb} \varphi^{}_{\mathrm{DSB-SC}}(t)\ne\Delta\varphi^{}_R\ne\Delta\theta^{}_R$$

%\begin{dmath}
%I_{3} =
%%
%\sum_{k=1}^{\infty}{\frac{\left(\frac{c}{\bar{\gamma}\pi ^{\frac{3}{2}}}\right)(-1)^{k+1}\left (\frac{K}{\sqrt{a_{10}}}\right )^{2k-1}\Gamma \left (p+\frac{1}{2}\right )}{(2k-1)(k-1)!\Gamma (p+1)}}\left \{E_{4k-2}\left (\frac{1}{\bar{\gamma }}\right )\delta (p)+\frac{1}{2\bar{\gamma}\sqrt{\pi}} \right . \times
%%
%\sum_{p=1}^{\infty}\left(\frac{(-1)^{p}(2k-1)(2k-3)\ldots (2k-(2p-3))}{2^{p}p!} \right . \times
%%
%\left.\left.  \frac {b^{p}\Gamma(p+\frac{1}{2})}{\Gamma(p+1)} E_{4k-2}\left (\frac{1}{\bar{\gamma}}\right )\right )\right \}.
%\end{dmath}

$$\begin{split} I_{3} &= \\ % &\sum_{k=1}^{\infty}{\frac{\left(\frac{c}{\bar{\gamma}\pi ^{\frac{3}{2}}}\right)(-1)^{k+1}\left (\frac{K}{\sqrt{a_{10}}}\right )^{2k-1}\Gamma \left (p+\frac{1}{2}\right )}{(2k-1)(k-1)!\Gamma (p+1)}}\left \{E_{4k-2}\left (\frac{1}{\bar{\gamma }}\right )\delta (p)+\frac{1}{2\bar{\gamma}\sqrt{\pi}} \right . \times\\ % &\sum_{p=1}^{\infty}\left(\frac{(-1)^{p}(2k-1)(2k-3)\ldots (2k-(2p-3))}{2^{p}p!} \right . \times \\ % &\left.\left. \frac {b^{p}\Gamma(p+\frac{1}{2})}{\Gamma(p+1)} E_{4k-2}\left (\frac{1}{\bar{\gamma}}\right )\right )\right \}. \end{split}$$

\end{document}


I commented out the problematic parts. The desired output should be like this:

If I uncomment the commented lines, I get Gamma as \prime symbol. I appreciate your help.

• Unfortunately, breqn makes some default assumptions about the font slots where characters and symbols are taken from, which fail in case some packages are loaded, which differ from the standard setup (note that newtxmath has good reasons for doing this). May 7 '15 at 16:30

The flexisym package makes some assumptions about the font slots characters and symbols are taken from. However, newtxmath has different ideas from the standard setup and for good reasons, because it provides many more symbols.

For fixing uppercase Greek letters here is a workaround:

\documentclass[a4paper,oneside,12pt]{book}
\usepackage{lmodern}
\usepackage{newtxtext}
\usepackage[scaled=0.92]{helvet}
\usepackage{textcomp}
\usepackage{amsmath}
\usepackage[cmintegrals,bigdelims]{newtxmath}
%\usepackage{flexisym}
\usepackage{breqn}

\makeatletter
% newtxmath uses mathgroup lettersA for uppercase Greek
\edef\mg@Greek{\hexnumber@\symlettersA}
\makeatother

\begin{document}

Some alternative text goes here.
%
$$\label{eqdsb} \varphi^{}_{\mathrm{DSB-SC}}(t)\ne\Delta\varphi^{}_R\ne\Delta\theta^{}_R$$

\begin{dmath}
I_{3} =
%
\sum_{k=1}^{\infty}{\frac{\left(\frac{c}{\bar{\gamma}\pi ^{\frac{3}{2}}}\right)(-1)^{k+1}\left (\frac{K}{\sqrt{a_{10}}}\right )^{2k-1}\Gamma \left (p+\frac{1}{2}\right )}{(2k-1)(k-1)!\Gamma (p+1)}}\left \{E_{4k-2}\left (\frac{1}{\bar{\gamma }}\right )\delta (p)+\frac{1}{2\bar{\gamma}\sqrt{\pi}} \right . \times
%
\sum_{p=1}^{\infty}\left(\frac{(-1)^{p}(2k-1)(2k-3)\ldots (2k-(2p-3))}{2^{p}p!} \right . \times
%
\left.\left.  \frac {b^{p}\Gamma(p+\frac{1}{2})}{\Gamma(p+1)} E_{4k-2}\left (\frac{1}{\bar{\gamma}}\right )\right )\right \}.
\end{dmath}

$$\begin{split} I_{3} &= \\ % &\sum_{k=1}^{\infty}{\frac{\left(\frac{c}{\bar{\gamma}\pi ^{\frac{3}{2}}}\right)(-1)^{k+1}\left (\frac{K}{\sqrt{a_{10}}}\right )^{2k-1}\Gamma \left (p+\frac{1}{2}\right )}{(2k-1)(k-1)!\Gamma (p+1)}}\left \{E_{4k-2}\left (\frac{1}{\bar{\gamma }}\right )\delta (p)+\frac{1}{2\bar{\gamma}\sqrt{\pi}} \right . \times\\ % &\sum_{p=1}^{\infty}\left(\frac{(-1)^{p}(2k-1)(2k-3)\ldots (2k-(2p-3))}{2^{p}p!} \right . \times \\ % &\left.\left. \frac {b^{p}\Gamma(p+\frac{1}{2})}{\Gamma(p+1)} E_{4k-2}\left (\frac{1}{\bar{\gamma}}\right )\right )\right \}. \end{split}$$

\end{document}


Usage of breqn may simplify the input of complex formulas, but doesn't improve their quality. In my opinion, the output of breqn is in no way better than the manual one. Bot formulas are, of course, horrible.

In particular, breaking after \frac{1}{2\bar{\gamma}\sqrt{\pi}} is wrong in both cases. You can fix it in the manually broken version; fixing something with breqn is almost impossible.

• (Upvote)Thank you, this is a smart work-around. My document, however, contains many many horrible formulas like this one and I find other options (other than breqn) tedious to implement especially \left\{ ... \right . etc. Any advice on other alternatives for my case? May 7 '15 at 17:05