diff --git a/change_log.txt b/change_log.txt
index a52159fe..23e98e01 100644
--- a/change_log.txt
+++ b/change_log.txt
@@ -1,6 +1,7 @@
 ===== trunk  =====
 04.10.2011
 - bugfix assign() in plugins called in subtemplates did change value also in parent template
+- bugfix of problem introduced with r4342 on math plugin 
 
 ===== Smarty-3.1.2  =====
 03.10.2011
diff --git a/libs/plugins/function.math.php b/libs/plugins/function.math.php
index 60a92f40..f4d3f05e 100644
--- a/libs/plugins/function.math.php
+++ b/libs/plugins/function.math.php
@@ -24,8 +24,8 @@
 function smarty_function_math($params, $template)
 {
     static $_allowed_funcs = array(
-        'int' => true, 'abs' => true, 'ceil' => true, 'cos' => true, 'exp' => true, 'floor' => true, 
-        'log' => true, 'log10' => true, 'max' => true, 'min' => true, 'pi' => true, 'pow' => true, 
+        'int' => true, 'abs' => true, 'ceil' => true, 'cos' => true, 'exp' => true, 'floor' => true,
+        'log' => true, 'log10' => true, 'max' => true, 'min' => true, 'pi' => true, 'pow' => true,
         'rand' => true, 'round' => true, 'sin' => true, 'sqrt' => true, 'srand' => true ,'tan' => true
     );
     // be sure equation parameter is present
@@ -55,7 +55,7 @@ function smarty_function_math($params, $template)
     foreach($params as $key => $val) {
         if ($key != "equation" && $key != "format" && $key != "assign") {
             // make sure value is not empty
-            if (isset($val[0])) {
+            if (strlen($val)==0) {
                 trigger_error("math: parameter $key is empty",E_USER_WARNING);
                 return;
             }