Fit equation with long fraction in two column setting

Question

I have a an equation with a long fraction and at each derivation step the fraction gets longer and the final fraction looks something like this :

    \begin{equation*}
\begin{split}
\frac{\sum_{A} P(Y|C= B, Y, G = H, A, K=0) P(Y, X < R, A)P(Y, X < R, A)P(C= Z | Y, W > K, A, U=0) P(Y, X < R, A)}{\sum_{A} P(T = K| A,S < Q A, W=0) P(N = K, A)P(N = K, A)P(N = K, A)P(N = K, A)}\\
\end{split}
\end{equation*}

I am on two column setting and have viewed a couple of posts where they were able to break the fraction either because it has a short dominator or it contains summation that can be broken into multiple lines like in here, here2, and here3. But in my case I am summing over the products in the nominator and dominator.

score 1 · Answer 1 · answered Nov 03 '23 at 22:35

You can introduce named terms, and split things up

\documentclass[twocolumn]{article}
\usepackage{amsmath}
\begin{document}
\noindent X\dotfill X
\begin{equation}
\begin{split}
\frac
  {\sum_{A} P(Y|C= B, Y, G = H, A, K=0) P(Y, X < R, A)P(Y, X < R, A)P(C= Z | Y, W > K, A, U=0) P(Y, X < R, A)}
  {\sum_{A} P(T = K| A,S < Q A, W=0) P(N = K, A)P(N = K, A)P(N = K, A)P(N = K, A)}\
\end{split}
\end{equation}
\noindent X\dotfill X
\begin{align}
   &\frac{n}{d}\
\intertext{where}
  n&=\sum_{A}
  \left(\begin{aligned}
   &P(Y|C= B, Y, G = H, A, K=0)\
   &P(Y, X < R, A)P(Y, X < R, A)\
   &P(C= Z | Y, W > K, A, U=0)\
  &P(Y, X < R, A)
   \end{aligned}\right)\[5pt]
  d&=\sum_{A}
   \left(\begin{aligned}
  & P(T = K| A,S < Q A, W=0)\
   &P(N = K, A)P(N = K, A)\
   &P(N = K, A)P(N = K, A)
   \end{aligned}\right)
\end{align}
\noindent X\dotfill X
\end{document}

Thank you. I also have some long equations without fractions and will do it the way you illustrated. Thanks again — Moh, Nov 04 '23 at 00:18

Mico · Accepted Answer · 2023-11-04T01:57:02.537

The mathtools package, a superset of the amsmath package, provides a macro called \splitfrac, which can be nested, and lets users split long numerators and/or denominators into shorter, stacked parts. For the fraction at hand, it looks like applying 3 nested \splitfrac directives to the numerator (for a total of four rows) and 2 nested \splitfrac directives to the denominator (for a total of three rows) will get the job done.

Optionally, encase both the numerator and the denominator in \left( ... \right) pairs.

\documentclass[twocolumn]{article}
\usepackage{mathtools} % for \splitfrac
\let\P\relax % undefinet the `\P` macro
\DeclareMathOperator{\P}{P} % probability operator
\usepackage{lipsum} % filler text
\begin{document}
\begin{equation}
\frac{%
   \left(
   \splitfrac{\sum_{A} 
   \P(Y\mid C= B, Y, G = H, A, K=0)}
   {\splitfrac{\P(Y, X < R, A)
   \P(Y, X < R, A)}
   {\splitfrac{\P(C= Z \mid Y, W > K, A, U=0)}
   {\P(Y, X < R, A)}}}
   \right)
   }{%
   \left(
   \splitfrac{\sum_{A} 
   \P(T = K\mid A,S < Q A, W=0)}
   {\splitfrac{\P(N = K, A)\P(N = K, A)}
   {\P(N = K, A)\P(N = K, A)}}
   \right)
   }
\end{equation}
\lipsum[1][1-5] % some filler text
\end{document}

1

Thanks a lot this worked great. – Moh Nov 04 '23 at 00:12

Fit equation with long fraction in two column setting

2 Answers2