diff --git a/relalg.sty b/relalg.sty
index fa0983b..e9df0a9 100755
--- a/relalg.sty
+++ b/relalg.sty
@@ -9,6 +9,7 @@
 \NeedsTeXFormat{LaTeX2e}[2001/06/01]
 \ProvidesPackage{relalg}[2008/02/28 Relational algebra notation]
 
+\RequirePackage{amssymb}
 \RequirePackage{latexsym}
 \RequirePackage{graphics}
 % Graphics is needed so that we can scale the size of a couple of operators.
@@ -114,6 +115,14 @@
 \newcommand{\RelFullOuter}{\RelFullOuterJoin}
 \newcommand{\RelFOJ}{\RelFullOuterJoin}
 
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% semijoin operator
+\newcommand{\RelSemiJoin}{\ensuremath{\ltimes}}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% antijoin operator
+\newcommand{\RelAntiJoin}{\ensuremath{\triangleright}}
+
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %
@@ -138,6 +147,12 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %
 % $Log$
+% Revision 1.9  2010/12/12 07:27:30  nstanger
+% - Normalised the restrict, intersect and join macros.
+% - Refactored aggregate function macros into a single parameterised
+%   RelAaggregate macro.
+% - Fixed incorrect macro references in outer join macros.
+%
 % Revision 1.8  2010/12/12 04:40:39  nstanger
 % - Added extend operator.
 %