diff --git a/app/models/tag_alias.rb b/app/models/tag_alias.rb
index 2e5415eca..f67f5fd9a 100644
--- a/app/models/tag_alias.rb
+++ b/app/models/tag_alias.rb
@@ -18,7 +18,7 @@ class TagAlias < ActiveRecord::Base
       end
     end
     
-    alias_hash.values.uniq
+    alias_hash.values.flatten.uniq
   end
   
   def absence_of_transitive_relation
diff --git a/app/models/tag_implication.rb b/app/models/tag_implication.rb
index 1b44a318e..154a6fda3 100644
--- a/app/models/tag_implication.rb
+++ b/app/models/tag_implication.rb
@@ -12,7 +12,9 @@ class TagImplication < ActiveRecord::Base
   validate :absence_of_circular_relation
   
   def self.with_descendants(names)
-    ([names] + where(["antecedent_name IN (?)", Array(names)]).all.map {|x| x.descendant_names_array}).flatten
+    Cache.get_multi(names.flatten, "ti") do |name|
+      ([name] + where(["antecedent_name = ?", name]).all.map {|x| x.descendant_names_array}).flatten
+    end.values.flatten.uniq
   end
   
   def absence_of_circular_relation