So I use the following theorem environments, which are resetted in each section.
\newtheorem{definition}{Definition}[section]
\newtheorem{proposition}{Proposition}[section]
\newtheorem{lemma}{Lemma}[section]
So I have a counter for each theorem, i.e. for definition, proposition and lemma. But in the appendix, I want that definition, proposition and lemma share a counter, that is they get labeled consecutively.
In other words, after I start
\appendix
I would like to have the following numbering: Lemma A.1 Proposition A.2
instead of Lemma A.1 Proposition A.1
How can this be achieved? I have been trying a lot, but without success.
Thanks in advance!
EDIT: The following document illustrates my problem.
\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage{amsthm}
\begin{document}
\newtheorem{definition}{Definition}[section]
\newtheorem{proposition}{Proposition}[section]
\newtheorem{lemma}{Lemma}[section]
\section{First section}
\begin{definition}
test
\end{definition}
\begin{definition}
test2
\end{definition}
\begin{lemma}
testLemma
\end{lemma}
\appendix
\section{My appendix}
\begin{lemma}
THIS IS
\end{lemma}
\begin{proposition}
NOT THE WAY I WANT IT TO BE
\end{proposition}
\end{document}