<?xml version="1.0" encoding="UTF-8"?>

<record version="6" id="9730">
 <title>B-tree</title>
 <name>BTree</name>
 <created>2007-07-04 15:22:11</created>
 <modified>2007-07-05 21:06:14</modified>
 <type>Definition</type>
 <creator id="13753" name="Mathprof"/>
 <author id="13753" name="Mathprof"/>
 <classification>
	<category scheme="msc" code="68P05"/>
	<category scheme="msc" code="68P10"/>
 </classification>
 <defines>
	<concept>order </concept>
 </defines>
 <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
</preamble>
 <content>A \emph{B-tree of \PMlinkescapetext{order} $m$} is a \PMlinkname{balanced}{BalancedTree} search tree in 
which 
\begin{itemize}
\item
every node has at most $m$ children,
\item 
every node, other than a root or leaf, has at least $m/2$ children,
\item
the root has at least 2 children if it is not a leaf,
\item
all leaf nodes appear on the same level
\item
a nonleaf node with $k$ children has $k-1$ keys.
\end{itemize}


If the tree has $n$ nodes its height is $O(log_2(n))$.
</content>
</record>
