diff --git a/app/views/wiki/tex.rhtml b/app/views/wiki/tex.rhtml
index 0c5b8380..ec637222 100644
--- a/app/views/wiki/tex.rhtml
+++ b/app/views/wiki/tex.rhtml
@@ -83,6 +83,11 @@
 \def\slash{\protect\itex@pslash}
 \makeatother
 
+% math-mode versions of \rlap, etc
+% from Alexander Perlis, "A complement to \smash, \llap, and lap"
+%   http://math.arizona.edu/~aprl/publications/mathclap/
+\def\clap#1{\hbox to 0pt{\hss#1\hss}}
\def\mathllap{\mathpalette\mathllapinternal}
\def\mathrlap{\mathpalette\mathrlapinternal}
\def\mathclap{\mathpalette\mathclapinternal}
\def\mathllapinternal#1#2{\llap{$\mathsurround=0pt#1{#2}$}}
\def\mathrlapinternal#1#2{\rlap{$\mathsurround=0pt#1{#2}$}}
\def\mathclapinternal#1#2{\clap{$\mathsurround=0pt#1{#2}$}}
+
 % Renames \sqrt as \oldsqrt and redefine root to result in \sqrt[#1]{#2}
 \let\oldroot\root
 \def\root#1#2{\oldroot #1 \of{#2}}
diff --git a/test/functional/wiki_controller_test.rb b/test/functional/wiki_controller_test.rb
index dde7b9fe..6f0689fa 100755
--- a/test/functional/wiki_controller_test.rb
+++ b/test/functional/wiki_controller_test.rb
@@ -1007,6 +1007,11 @@ class WikiControllerTest < ActionController::TestCase
 \def\slash{\protect\itex@pslash}
 \makeatother
 
+% math-mode versions of \rlap, etc
+% from Alexander Perlis, "A complement to \smash, \llap, and lap"
+%   http://math.arizona.edu/~aprl/publications/mathclap/
+\def\clap#1{\hbox to 0pt{\hss#1\hss}}
\def\mathllap{\mathpalette\mathllapinternal}
\def\mathrlap{\mathpalette\mathrlapinternal}
\def\mathclap{\mathpalette\mathclapinternal}
\def\mathllapinternal#1#2{\llap{$\mathsurround=0pt#1{#2}$}}
\def\mathrlapinternal#1#2{\rlap{$\mathsurround=0pt#1{#2}$}}
\def\mathclapinternal#1#2{\clap{$\mathsurround=0pt#1{#2}$}}
+
 % Renames \sqrt as \oldsqrt and redefine root to result in \sqrt[#1]{#2}
 \let\oldroot\root
 \def\root#1#2{\oldroot #1 \of{#2}}
diff --git a/test/unit/page_renderer_test.rb b/test/unit/page_renderer_test.rb
index 3cbd2967..d50f9322 100644
--- a/test/unit/page_renderer_test.rb
+++ b/test/unit/page_renderer_test.rb
@@ -212,6 +212,13 @@ END_THM
   
   def test_have_latest_itex2mml  
 
+      assert_markup_parsed_as(
+        %{<p>equation <math class='maruku-mathml' displa} +
+        %{y='inline' xmlns='http://www.w3.org/1998/Math/} +
+        %{MathML'><mi>A</mi><mpadded lspace='-100%width'} +
+        %{ width='0'><mi>B</mi></mpadded></math></p>},
+        "equation $A \\mathllap{B}$")
+
       assert_markup_parsed_as(
         %{<p>equation <math class='maruku-mathml' displa} +
         %{y='inline' xmlns='http://www.w3.org/1998/Math/} +
@@ -247,8 +254,8 @@ END_THM
 
     assert_markup_parsed_as(
         %{<p>\\rlap: <math class='maruku-mathml' display='} +
-        %{inline' xmlns='http://www.w3.org/1998/Math/MathML'><mpadded} +
-        %{ width='0'><mn>123</mn></mpadded></math></p>},
+        %{inline' xmlns='http://www.w3.org/1998/Math/MathML'>} +
+        %{<mn>123</mn></math></p>},
         '\rlap: $\rlap{123}$')
   end