Numbering Theorem, definition, Proposition, Corollary, Remark by section consecutively without repetition

Question

I am writing a paper for publication in Springer journal using svjourclass, and I am using the following set of commands

\RequirePackage{fix-cm}

\documentclass[smallextended,envcountsect]{svjour3} 

\smartqed  % flush right qed marks, e.g. at end of proof
\usepackage{graphicx}  

\usepackage{amsmath}
\usepackage{mathtools}
\usepackage{amssymb} 
\usepackage{graphicx} 
\usepackage{epstopdf}
\usepackage[titletoc,title]{appendix}% for appendix met A
\usepackage{color} 
\usepackage{booktabs} 
\usepackage{float} 
\usepackage{dcolumn}

\newcounter{chapter} % to fix the bug in svjour3
\usepackage{cleveref} 

\spnewtheorem{thm}{Theorem}[section]{\bfseries}{\itshape}  
\spnewtheorem{cor}[theorem]{Corollary}{\bfseries}{\itshape}
\spnewtheorem{lem}[theorem]{Lemma}{\bfseries}{\itshape}
\spnewtheorem{ntn}[theorem]{Notations}{\bfseries}{\itshape} 
\spnewtheorem{pro}[theorem]{Proposition}{\bfseries}{\itshape} 
\spnewtheorem{dfn}[theorem]{Definition}{\bfseries}{\itshape}   
\spnewtheorem{as}[theorem]{Assumption}{\bfseries}{\itshape}
\spnewtheorem{rem}[theorem]{Remark}{\bfseries}{\itshape}
\spnewtheorem{ob}[theorem]{Observation}{\bfseries}{\itshape}   

Now when I write with a \section{} for example 

\begin{dfn} 

\end{dfn} 

\begin{thm}  

\end{thm}



\begin{rem} 

\end{rem} 

\begin{lem} 

\end{lem} 


\begin{pro} 

\end{pro} 

\begin{cor} 

\end{cor}

\begin{pro}

\end{pro}

\begin{dfn}  

\end{dfn} 

what I am getting is

Definition 2.1 Theorem 2.1 Remark 2.2 Lemma 2.3 Proposition 2.4 Corollary 2.5 Proposition 2.6 Definition 2.7

Now I am not sure why the numbering of the first two Definition and Theorem are being repeated. What I do actually want is just usual like

Definition 2.1

Theorem 2.2

Remark 2.3

Lemma 2.4

Proposition 2.5

Corollary 2.6

Proposition 2.7

Can someone please help me in getting the right code for such display?

Thanks in advance.

Answer 1

You have requested that the cor, lem, etc. environments be numbered like theorem and not thm.

That said, you should probably use the predefined environments provided by the class, rather than your own. Note, for example, that they specify different formatting for remark. See the documentation for more details.

Answer 2

The numbering is presumably defined by the journal (you are using their recommended packages as directed, yes?). If so, the decision to number just this way is part of the journal's style, and trying to do it differently will just get your work rejected for not complying with the guidelines.