How Can I Resolve the ntheorem Error in Latex?

[Theoretiker]

Hello,

I have a problem with Latex. I use MikeTex as Latex distribution and TexnicCenter as editor. I want the code for a mathematical sentence with proof. I used the package ntheorem and I got the mistake:

Package ntheorem Error: Theoremstyle plain already defined

Waht did they mean with "already defined"?

My code is:

\documentclass[12pt,a4paper]{article} 
\usepackage[latin1]{inputenc} 
\usepackage[ngerman]{babel} 
\usepackage[T1]{fontenc} 
\usepackage{amsmath,amsgen,amscd,amsrefs,amsthm,amsopn,amssymb} 
\usepackage{graphicx} 
\usepackage{xcolor} 
[B]\usepackage[thmmarks]{ntheorem} [/B]



\begin{document} 


%ntheorem Umgebung 
\theoremstyle{nonumberplain} 
\theoremheaderfont{% 
\normalfont\scshape} 
\theorembodyfont{\normalfont} 
\theoremsymbol{\rule{.5em}{.5em}} 
\newtheorem{satz}{Satz:} 
\newtheorem{beweis}{Beweis:} 
\begin{satz} 
$1$ ist grö"ser als $0$. 
\begin{beweis} 
Da $1 = 1 \cdot 1$, ist $1$ eine Quadratzahl, und Quadratzahlen ungleich~$0$ sind immer grö"ser als~$0$. 
\end{beweis} 
\end{satz} 


\end{document}

Thanks for help :)

greetings

 

[CompuChip]

I don't know what ntheorem does, but maybe it is in conflict with another package. Try taking out amsthm, for example.

By the way, I don't think grö"ser will work, you probably want something like gr\"oser

 

[las3rjock]

ntheorem.sty interferes with amsmath.sty and amsthm.sty. See section 3.2 of http://www.ctan.org/tex-archive/macros/latex/contrib/ntheorem/ntheorem.pdf

 

[Theoretiker]

Hi,

thanks for help. Yes it was AMS :(

The AMS-package is such important for me that probably I will disclaim the ntheorem-package.

Now, I guess I will use \Box as symbol for the end of a proof and put it right-aligned

greetings

 

[CompuChip]

You can use amsmath, according to the documentation linked to by las3rjock. You can also get some of the amsthm options by using amsthm as an option to ntheorem.

Or you can just not spend any time reading such a document and do it the ugly way