diff --git a/relalg.sty b/relalg.sty
index 0930305..fa0983b 100755
--- a/relalg.sty
+++ b/relalg.sty
@@ -23,7 +23,7 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % select or restrict operator
 \newcommand{\RelSelect}{\ensuremath{\sigma}}
-\newcommand{\RelRestrict}{\ensuremath{\sigma}}
+\newcommand{\RelRestrict}{\RelSelect}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % project operator
@@ -59,13 +59,13 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % set intersection operator
 \newcommand{\RelIntersection}{\ensuremath{\cap}}
-\newcommand{\RelIntersect}{\ensuremath{\cap}}
+\newcommand{\RelIntersect}{\RelIntersection}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % natural join operator
 \newcommand{\RelNaturalJoin}{\ensuremath{\Join}}
-\newcommand{\RelNatJoin}{\ensuremath{\Join}}
-\newcommand{\RelNJoin}{\ensuremath{\Join}}
+\newcommand{\RelNatJoin}{\RelNatJoin}
+\newcommand{\RelNJoin}{\RelNJoin}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % division operators
@@ -85,33 +85,34 @@
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % aggregate functions
-\newcommand{\RelSum}[1]{\ensuremath{\mathcal{G}_{\mathbf{\mathrm{sum}}(#1)}}}
-\newcommand{\RelAvg}[1]{\ensuremath{\mathcal{G}_{\mathbf{\mathrm{avg}}(#1)}}}
-\newcommand{\RelMin}[1]{\ensuremath{\mathcal{G}_{\mathbf{\mathrm{min}}(#1)}}}
-\newcommand{\RelMax}[1]{\ensuremath{\mathcal{G}_{\mathbf{\mathrm{max}}(#1)}}}
-\newcommand{\RelCount}[1]{\ensuremath{\mathcal{G}_{\mathbf{\mathrm{count}}(#1)}}}
+\newcommand{\RelAggregrate}[2]{\ensuremath{\mathcal{G}_{\mathbf{\mathrm{#1}}(#2)}}}
+\newcommand{\RelSum}[1]{\RelAggregrate{sum}{#1}}
+\newcommand{\RelAvg}[1]{\RelAggregrate{avg}{#1}}
+\newcommand{\RelMin}[1]{\RelAggregrate{min}{#1}}
+\newcommand{\RelMax}[1]{\RelAggregrate{max}{#1}}
+\newcommand{\RelCount}[1]{\RelAggregrate{count}{#1}}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % outer join operators
 % Note: can't use \ensuremath in these because it screws up the spacing.
 % The $ are OK though because they're used inside hboxes anyway.
 \newcommand{\RelLeftOuterJoin}{\scalebox{0.5}[1]{$\sqsupset$}\mkern-2.5mu\lower0.1em\hbox{$\Join$}}
-\newcommand{\RelleftOuterJoin}{\LeftOuterJoin}
-\newcommand{\RelLOuterJoin}{\LeftOuterJoin}
-\newcommand{\RelLeftOuter}{\LeftOuterJoin}
-\newcommand{\RelLOJ}{\LeftOuterJoin}
+\newcommand{\RelleftOuterJoin}{\RelLeftOuterJoin}
+\newcommand{\RelLOuterJoin}{\RelLeftOuterJoin}
+\newcommand{\RelLeftOuter}{\RelLeftOuterJoin}
+\newcommand{\RelLOJ}{\RelLeftOuterJoin}
 
 \newcommand{\RelRightOuterJoin}{\lower0.1em\hbox{$\Join$}\mkern-2.5mu\scalebox{0.5}[1]{$\sqsubset$}}
-\newcommand{\RelrightOuterJoin}{\RightOuterJoin}
-\newcommand{\RelROuterJoin}{\RightOuterJoin}
-\newcommand{\RelRightOuter}{\RightOuterJoin}
-\newcommand{\RelROJ}{\RightOuterJoin}
+\newcommand{\RelrightOuterJoin}{\RelRightOuterJoin}
+\newcommand{\RelROuterJoin}{\RelRightOuterJoin}
+\newcommand{\RelRightOuter}{\RelRightOuterJoin}
+\newcommand{\RelROJ}{\RelRightOuterJoin}
 
 \newcommand{\RelFullOuterJoin}{\scalebox{0.5}[1]{$\sqsupset$}\mkern-2.5mu\lower0.1em\hbox{$\Join$}\mkern-2.5mu\scalebox{0.5}[1]{$\sqsubset$}}
-\newcommand{\RelfullOuterJoin}{\FullOuterJoin}
-\newcommand{\RelFOuterJoin}{\FullOuterJoin}
-\newcommand{\RelFullOuter}{\FullOuterJoin}
-\newcommand{\RelFOJ}{\FullOuterJoin}
+\newcommand{\RelfullOuterJoin}{\RelFullOuterJoin}
+\newcommand{\RelFOuterJoin}{\RelFullOuterJoin}
+\newcommand{\RelFullOuter}{\RelFullOuterJoin}
+\newcommand{\RelFOJ}{\RelFullOuterJoin}
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -137,6 +138,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %
 % $Log$
+% Revision 1.8  2010/12/12 04:40:39  nstanger
+% - Added extend operator.
+%
 % Revision 1.7  2010/12/12 01:25:19  nstanger
 % - Normalised the logical AND/OR macros.
 %