Numbering theorems within chapters

Question

I've recently asked a question: Chapters in TeX

regarding working with chapters in tex. I have since learned that I must use documentclass report for the purposes of my document. However, now all of my Theorems, Corollaries, Remarks, and so forth are numbered "0.number.number" (with the first 0 never changing). I would like, at the very least, to understand how to make the first number denote the number of the chapter.

The current code I have is this:

\newtheorem{thm}{Theorem}[section]
\newtheorem{rmk}[thm]{Remark}
\newtheorem{qst}[thm]{Question}
\newtheorem{prp}[thm]{Proposition}
\newtheorem{hyp}[thm]{Hypotheses}
\newtheorem{crl}[thm]{Corollary}
\newtheorem{cnj}[thm]{Conjecture}
\newtheorem{lem}[thm]{Lemma}
\newtheorem{dff}[thm]{Definition}
\newtheorem{clm}[thm]{Claim}
\newtheorem{ntt}[thm]{Notation}
\numberwithin{equation}{section}

Answer 1

All LaTeX classes use the \thechapter,\thesection etc., to style the numbering of the various section numbers. You can redefine these to whatever you wish. In the example below, I have redefined the \thechapter and \thesection to remove the dot and the objectionable zero. This way you can still keep on using the \chapter command and you will have no problems with the Table of Contents. I personally dislike the use of star commands as they are very unsemantic if one can coin such a word.

\documentclass{report}
\makeatletter\renewcommand{\thechapter}{}
\renewcommand{\thesection}{\arabic{section}}
\renewcommand{\chaptername}{}
\makeatother

\newtheorem{thm}{Theorem}[section]
\begin{document}
\chapter{A chapter title}
\section{A section}
\begin{thm} A theorem \end{thm}
\end{document}

I have also removed the word chapter as it is meaningless, if there is no number.

If you want to number the sections with chapter numbers (but not show them in the Chapter head), use:

\renewcommand{\thesection}{\arabic{chapter}.\arabic{section}}

I am not too sure if this is a good idea though, as it will be confusing to the reader and have never seen such a style in any book.