Math & Science ⇒ Mathematical Proofs

[esong_98]

I want to write a mathematical proof after a theorem. My theorem package is working, but when I try to write the proof, I get a "Environment proof undefined" error. This is my current code I'm trying to use:

Code: Select all

\documentclass[12pt,a4paper,english,fleqn]{article}
\usepackage{mathptmx}

%The next three packages are special mathematical formatting packages used to handle long equations, theorems and proofs.
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath}

\newtheorem{theorem}{Theorem}
\usepackage[scaled=0.86]{helvet}
\renewcommand{\familydefault}{\rmdefault}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
%\usepackage{fancyhdr}
%\pagestyle{fancy}
\setcounter{secnumdepth}{2}
\usepackage{graphicx}
\usepackage[authoryear]{natbib}
%Define EconEJ colors
\usepackage{xcolor}
\definecolor{EconomicsGray}{RGB}{198,212,225}
\definecolor{EconomicsLightBlue}{RGB}{127,191,192}
\definecolor{EconomicsBlue}{RGB}{0,63,138}
\definecolor{EconomicsDarkBlue}{RGB}{0,63,117}

% You need this for the headers:
\usepackage{graphicx}
\usepackage{lscape}


% Caption formatting
\usepackage[font=footnotesize,labelfont=bf]{caption}


% Reduce font size for section
\makeatletter
\renewcommand\section{\@startsection{section}{1}{\z@}
{-5ex \@plus -1ex \@minus -.2ex}{2.3ex \@plus.2ex}{\normalfont\large\bf}}

%Reduce font size for subsection
\renewcommand\subsection{\@startsection{subsection}{2}
{\z@}{-3.25ex\@plus -1ex \@minus -.2ex}{1.5ex \@plus .2ex}{\normalfont\bf}}


% Enforce proper line breaks and avoid widows and orphans
\tolerance 1414
\hbadness 1414
\emergencystretch 1.5em
\hfuzz 0.3pt
\widowpenalty = 10000
\clubpenalty=10000
\vfuzz \hfuzz
\raggedbottom
% Format footnotes

% Footnote formatting
\usepackage[hang]{footmisc}
\renewcommand{\hangfootparindent}{1em}
\renewcommand{\hangfootparskip}{0em}
\renewcommand{\footnotemargin}{0.00001pt}
\def\footnotelayout{\hspace{1em}}

%Appendix
\usepackage{appendix}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Place your own additions to the preable HERE, that is, BEFORE the following
% call to hyperref

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%Hyperlink settings for linkcolors and initial view
\usepackage[%
colorlinks=true,%
linkcolor=black,%
citecolor=black,%
urlcolor=EconomicsDarkBlue,%
pdfstartview=FitH,%
pdfview=FitH,%
pdfpagemode=UseNone]{hyperref}
\hypersetup{pdftitle={Economics: The Open Access, Open Assessment E-Journal}}

% Define font for hyperlinks
\def\UrlFont{\normalfont}

% Some fine-tuning of layout
\usepackage{microtype}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Put your additions to the preable above the call to hyperref, not here, unless you
% want to modify hyperref settings, as is the case with the precvious two commands

\@ifundefined{showcaptionsetup}{}{%
 \PassOptionsToPackage{caption=false}{subfig}}
\usepackage{subfig}
\AtBeginDocument{
  \def\labelitemi{\tiny\(\bullet\)}
}
\makeindex
\makeatother
\setlength\intextsep{0pt plus 1pt minus 1pt}
\usepackage{babel}
\usepackage{graphicx}
\usepackage{setspace}

\begin{document}

\begin{theorem}
If $CO_2$, $M$, emissions are always positive and never converging to zero, then the economy eventually suffers 100 percent damage or $\hat{\Omega} \rightarrow 1$ as time $t \rightarrow  \infty$.
\end{theorem}

\begin{proof} 
Assuming no emissions into the biosphere or oceans, the concentration of $CO_2$ at $t=t+m$ is given by equation (11) or $\dot{M}(t+n) = \varpi \displaystyle\sum_{i=1}^{N} \dot{m}(t+i) + (1-\varpi) \displaystyle\sum_{i=0}^{N} (1-\delta_p)^i \dot{m}(t+N-i) + \dot{M}^e(t)$. 
\end{proof}
\end{document}

_________________________________________________

Apparently I'm missing a usepackage or sometype of command to get my proof formated. Any suggestions? By the way, the proof is still incomplete so it doesn't make sense yet.

[Johannes_B]

This might be confusing, but all you need to add is \newtheorem{proof}{ESONG PROOF}.


Do you understand the pieces of code you have there? Some of it is pretty confusing.

[esong_98]

Thanks, that would have been the simplest way to solve the problem. However, after an hour or two of research I discovered to get everything I wanted I added:

Code: Select all

\usepackage{amsthm}
\usepackage{amssymb}

Those packages pretty much led to the format I wanted.

To answer your question. No I don't fully understand the full code of my preamble, as much of it comes from a standard package for economic journals.