I am writing some lecture notes for a course on overleaf.

```
\documentclass[a4paper,11pt,openany]{book}
\usepackage[utf8]{inputenc}
\usepackage{amsmath,amssymb,amsthm}
\usepackage[colorlinks=true]{hyperref}
\theoremstyle{definition}
\newtheorem{theorem}{Theorem}[chapter]
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{definition}[theorem]{Definition}
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{proposition}[theorem]{Proposition}
\newtheorem{example}[theorem]{Example}
\newtheorem*{notation}{Notation}
\newtheorem*{note}{Note}
\newtheorem*{solution}{Solution}
\def\bse{\begin{equation*}}
\def\ese{\end{equation*}}
\def\bp{\begin{proposition}}
\def\ep{\end{proposition}}
\def\bt{\begin{theorem}}
\def\et{\end{theorem}}
\begin{document}
%some text
\bt
\label{t:theorem_bla}
bla
\et
\bp
\label{p:deg}
Let $K\ss L$ be fields and let $\a \in L$ be algebraic over $K$. Then:
\bse
[K(\a):K]=\deg P_{min}(\a,K) \, .
\ese
\ep
%some more text
Hence, by \autoref{p:deg}, we have:
%even more text
\end{document}
```

I just recently found out about the `\autoref`

command provided by the `hyperref`

package. Quite pleased with it, it worked fine showing the correct label for my custom theorem environments (lemmas, prepositions, etc.).

However, I realised that at some point all the labels appeared as "Theorem" instead. I don't recall making any changes to the preamble in that short amount of time. Also, I have read this question:

How to get correct autoref for theorems

However, I didn't have `\<name>autorefname`

in the preamble before and it worked…

I have tried to compile it on my MiKTeX and I get the same output, so this doesn't seem to be related to Overleaf.

## Best Answer

The problem arises because the

`theorem`

,`corollary`

,`definition`

,`lemma`

, and`proposition`

environments all share the same counter.The quickest solution I can think of is to (a) add the instruction

after loading the

`hyperref`

package and (b) replace all instances of`\autoref`

with`\cref`

.Aside: I can't help but remark that your document suffers from a gross overuse of

`\left`

and`\right`

to autosize the "fence symbols" (parentheses, brackets, etc.). In many cases I've looked at, omitting the`\left`

and`\right`

instructions would definitely be the (typographically) correct thing to do.