# inserting sentences between subequations

My apologies for asking so many questions here. I want to introduce a sentence in between 2 subequations which is not in math mode. Here is the code that I am using:

   \documentclass[12pt,oneside,reqno]{amsart}
\usepackage{amssymb}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\begin{document}
\begin{subequations}
\begin{align}
x=1222222222222222\\
Here x is an arbitrary constant\\
y=2
\end{align}
\end{subequations}
\end{document}​


In the output, the line Here x is an arbitrary constant appears in math mode. Also y=2 is aligned towards the right which is something I don't want. Is it possible to include the sentence inside the subequations not in math mode. Also how do I align y=2 along with x in the center?

-

A look through the amsmath manual (texdoc amsmath) will be beneficial. The intertext command may be what you're after, alignment points are specified with &:

\documentclass[12pt,oneside,reqno]{amsart}
\usepackage{amssymb}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\begin{document}
\begin{subequations}
\begin{align}
x&=1222222222222222\\
\intertext{Here $x$ is an arbitrary constant}
y&=2
\end{align}
\end{subequations}
\end{document}​


-
A quick follow-up note to the OP: in order for the \intertext command to work, you needn't be in the align environment; for instance, the gather environment, which (unsurprisingly) does not align the equations on some point, will also work. – Mico Oct 26 '11 at 12:12

As Torbjørn pointed out, the \intertext-command from amsmath allows to add normal text within an align-environment (or similar) while keeping the alignement points.

\documentclass{scrartcl}

\usepackage{amsmath}
\usepackage{mathtools}

\begin{document}

\begin{align}
a &= b \\
c &= d
\intertext{Some text}
e &= f
\end{align}


It should be mentioned, however, that Morten Hoegholm's package mathtools (which provides several corrections for and additions to amsmath), corrects a slight problem of \intertext and provides a new command \shortintertext with less spacing.

\begin{align}
a &= b \\
c &= d
\shortintertext{Some text}
e &= f
\end{align}


In addition to this, there are options to fine-tune spacing.

% (This works, in contrast to what can be found in the current version of the manual.)
\mathtoolsset{
aboveshortintertextdim=20pt, % (default: 3pt)
belowshortintertextdim=10pt, % (default: 3pt)
}

\begin{align}
a &= b \\
c &= d
\shortintertext{Some text with excessive spacing}
e &= f
\end{align}

\end{document}


-