# Cleveref's \crefrange and mixed equations and subequations

The line Refer to \crefrange{eqa}{eqc}. gives the output:

Refer to ?? 1–3.

It used to work before.

Can anyone explain how to fix it?

\documentclass{article}

\usepackage{amsmath,cleveref}

\begin{document}

\begin{subequations}
\label{eqa}
\begin{align}
a &= b\\
c &= d
\end{align}
\end{subequations}

\begin{subequations}
\label{eqba}
\begin{align}
e &= f\\
g &= h
\end{align}
\end{subequations}

$$\label{eqc} i = j$$

Refer to \crefrange{eqa}{eqc}.

\end{document}
• I get it right. Did you compile at least twice? – user11232 Jan 15 '14 at 1:58
• Yes I ran it twice but keep getting the LaTeX Warning: References eqa' and eqc' in reference range on page 1 have different types subequation' and equation' on input line 28. – user41974 Jan 15 '14 at 2:11
• Some thing else is going on. With your code above I get Refer to eqs. (1) to (3). – user11232 Jan 15 '14 at 2:12
• Im running Miktex 2.9. What are you running? – user41974 Jan 15 '14 at 2:16
• I can confirm the bad behavior; in version 0.19 a modification to the management of subequations has been done, which apparently broke the functionality. – egreg Jan 15 '14 at 7:44

(Answer based on this post and @egreg's comment that the subequations environment management has changed.)

You can force the top-level label of the subequations environment to be treated as an equations-environment label through an optional argument to \label:

\begin{subequations}
\label[equation]{eqlabel}
[...]
\end{subequations}

Your MWE would look like this (extra sub-equation labels added to show this does not affect the top-level label behaviour):

\documentclass{article}

\usepackage{amsmath,cleveref}

\begin{document}

\begin{subequations}
\label[equation]{eqa}
\begin{align}
\label{subeqa1}
a &= b \\
\label{subeqa2}
c &= d
\end{align}
\end{subequations}

\begin{subequations}
\label[equation]{eqb}
\begin{align}
\label{subeqb1}
e &= f \\
\label{subeqb2}
g &= h
\end{align}
\end{subequations}

$$\label{eqc} i = j$$

Refer to \crefrange{eqa}{eqc}.

\end{document}

### EDIT: The downside

It appears that labels declared as \label[equation]{...} are overlooked by RefTeX. This makes it a little less convenient to add references to top-level labels of a set of sub-equations if one is used to using RefTeX. I imagine there should be a simple way to fix this, but I do not know how.

I faced the same problem with version 0.19 of cleveref (see the above comment by egreg). I fixed this behaviour by

\crefalias{subequation}{equation}

in the preamble.

(Please drop a comment if this fix is somehow dirty or should be avoided)