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Viewing Version 2 of 'proper subgroup'
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Title of object: proper subgroup
Canonical Name: ProperSubgroup
Type: Definition

Created on: 2002-06-27 19:44:33
Modified on: 2002-06-28 05:58:52

Creator: yark
Modifier: yark
Author: imran

Classification: msc:20A99
Defines: proper subgroup, improper subgroup

Revision comment (for changes between this and next version):

correction #9997

Preamble:

% this is the default PlanetMath preamble. as your knowledge
% of TeX increases, you will probably want to edit this, but
% it should be fine as is for beginners.

% almost certainly you want these
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}

% used for TeXing text within eps files
%\usepackage{psfrag}
% need this for including graphics (\includegraphics)
%\usepackage{graphicx}
% for neatly defining theorems and propositions
%\usepackage{amsthm}
% making logically defined graphics
%\usepackage{xypic}

% there are many more packages, add them here as you need them

% define commands here
Content:

A group $H$ is a \emph{proper subgroup} of a group $G$ if and only if $H$ is a subgroup of $G$ and \begin{equation}H \neq G.\end{equation}
Similarly a group $H$ is an \emph{improper subgroup} of a group $G$ if and only if $H$ is a subgroup of $G$ and \begin{equation}H=G.\end{equation}