diff --git a/jsonld.php b/jsonld.php
index cbab03c..20f9b98 100644
--- a/jsonld.php
+++ b/jsonld.php
@@ -1071,7 +1071,7 @@ class JsonLdProcessor {
     }
 
     // 2. equal @values
-    if(self::_isValue($v1) || self::_isValue($v2)) {
+    if(self::_isValue($v1) && self::_isValue($v2)) {
       return (
         self::_compareKeyValues($v1, $v2, '@value') &&
         self::_compareKeyValues($v1, $v2, '@type') &&
@@ -1538,9 +1538,9 @@ class JsonLdProcessor {
           if(property_exists($active_ctx->mappings, $active_property)) {
             $mapping = $active_ctx->mappings->{$active_property};
             if($mapping && $mapping->propertyGenerator) {
-              $this->_findAndRemovePropertyGeneratorDuplicates(
+              $this->_findPropertyGeneratorDuplicates(
                 $active_ctx, $element, $expanded_property, $expanded_item,
-                $active_property);
+                $active_property, true);
             }
           }
 
@@ -3647,14 +3647,8 @@ class JsonLdProcessor {
         // see if a property generator matches
         if(is_object($parent)) {
           foreach($term_info->propertyGenerators as $property_generator) {
-            $iris = $active_ctx->mappings->{$property_generator}->{'@id'};
-            $match = true;
-            foreach($iris as $iri_) {
-              if(!property_exists($parent, $iri_)) {
-                $match = false;
-                break;
-              }
-            }
+            $match = $this->_findPropertyGeneratorDuplicates(
+              $active_ctx, $parent, $iri, $value, $property_generator, false);
             if($match) {
               $term = $property_generator;
               break;
@@ -3952,8 +3946,8 @@ class JsonLdProcessor {
   }
 
   /**
-   * Finds and removes any duplicate values that were presumably generated by
-   * a property generator in the given element.
+   * Finds and, if specified, removes any duplicate values that were
+   * presumably generated by a property generator in the given element.
    *
    * @param stdClass $active_ctx the active context.
    * @param stdClass $element the element to remove duplicates from.
@@ -3961,30 +3955,64 @@ class JsonLdProcessor {
    *          generator.
    * @param mixed $value the value to compare against when duplicate checking.
    * @param string $active_property the property generator term.
+   * @param bool $remove true to remove the duplicates found, false not to.
+   *
+   * @return bool true if duplicates were found for every IRI.
    */
-  protected function _findAndRemovePropertyGeneratorDuplicates(
-    $active_ctx, $element, $expanded_property, $value, $active_property) {
+  protected function _findPropertyGeneratorDuplicates(
+    $active_ctx, $element, $expanded_property, $value, $active_property,
+    $remove) {
+    $rval = true;
+
     // get property generator IRIs
     $iris = $active_ctx->mappings->{$active_property}->{'@id'};
 
     // for each IRI that isn't 'expandedProperty', remove a single duplicate
     // from element, if found
     foreach($iris as $iri) {
+      if($rval === false) {
+        break;
+      }
+
       if($iri === $expanded_property) {
         continue;
       }
+
+      $rval = false;
+      if(!property_exists($element, $iri)) {
+        break;
+      }
+
       $length = count($element->{$iri});
+
+      // handle empty array case
+      if($length === 0 && is_array($value) && count($value) === 0) {
+        $rval = true;
+        if($remove) {
+          unset($element->{$iri});
+        }
+        continue;
+      }
+
+      // handle other cases
       for($pi = 0; $pi < $length; ++$pi) {
         if(self::compareValues($element->{$iri}[$pi], $value)) {
-          // duplicate found, remove it in place
-          array_splice($element->{$iri}, $pi, 1);
-          if(count($element->{$iri}) === 0) {
-            unset($element->{$iri});
+          // duplicate found
+          $rval = true;
+
+          if($remove) {
+            // remove it in place
+            array_splice($element->{$iri}, $pi, 1);
+            if(count($element->{$iri}) === 0) {
+              unset($element->{$iri});
+            }
           }
           break;
         }
       }
     }
+
+    return $rval;
   }
 
   /**