Problems with theorem/definition/statement numbering

Question

I have theorems, definitions, statements, that look like as follows \section{1} \subsection{1} Theorem 1.1.1 .... Statement 1.1.2 .... Definition 1.1.3....

\subsection{2}

Theorem 1.2.1 .... Statement 1.2.2 .... Definition 1.2.3....

---

Instead of it, I want to have this:

\section{1} \subsection{1} Theorem 1.1 .... Statement 1.2 .... Definition 1.3....

\subsection{2}

Theorem 2.1 .... Statement 2.2 .... Definition 2.3....

---

i.e in my document I do not need at all section numbering in these environments. What shall I to do?

Answer 1

With package remreset the reset dependencies can be removed. For example, if counter theorem is reset if counter subsection is incremented, then

\usepackage{remreset}
\makeatletter
\@removefromreset{theorem}{subsection}
\makeatother

the resetting is removed.

The other way \@addtoreset does not need a package. For example, if counter theorem should be reset if counter section is incremented:

\makeatletter
\@addtoreset{theorem}{section}
\makeatother

The appearance of the counter is controlled by \the<counter>. For example, in the latter case it could be redefined to:

\renewcommand*{\thetheorem}{\thesection.\arabic{theorem}}

Macro \numberwithin of package amsmath performs both steps, adding reset dependency and renaming \the<counter>:

\usepackage{amsmath}
\numberwithin{theorem}{section}

I hope, you get the idea. A minimal working example is missing. Thus it is not clear to me, what you are doing. Especially the numbering inside subsections is quite unusual. Perhaps it is wise to check the preamble if this is not intended.

Also it looks even more odd, if the numbering occurs inside subsections without the section number, but with subsection number. The numbers are not unique, thus it is not clear which theorems are meant if only the reference is given.

I would keep the numbering scheme easy and understandable:

• Plain numbers without resetting at all: Theorem 1, Theorem 2, …

  1. First chapter
  Theorem 1
  Theorem 2
  2. Second chapter
  Theorem 3
  Theorem 4
  

• Numbering in a large entity like chapter or section, if the class does not provide chapters:

  1. First chapter  
  Theorem 1.1
  Theorem 1.2
  2. Second chapter
  Theorem 2.1
  Theorem 2.2
  

Then the reader has a chance to understand the numbering without going in deciphering mode.

Answer 2

You probably have

\newtheorem{theorem}{Theorem}[subsection]
\newtheorem{statement}[theorem]{Statement}
\newtheorem{definition}[theorem]{definition}

in order to bind the numbering to the subsection counter and the three environments share the same theorem counter.

What you need is

\renewcommand{\thetheorem}{\arabic{subsection}.\arabic{theorem}}

However, you'll get ambiguous numbering, as the first theorem in section 1, subsection 1 will be numbered 1.1, just like the numbering of the first theorem in section 2, subsection 1.