diff --git a/Data/Profunctor/Sieve.idr b/Data/Profunctor/Sieve.idr
index e69de29..152707c 100644
--- a/Data/Profunctor/Sieve.idr
+++ b/Data/Profunctor/Sieve.idr
@@ -0,0 +1,15 @@
+module Data.Profunctor.Sieve
+
+import Data.Profunctor
+
+%default total
+
+
+public export
+interface (Profunctor p, Functor f) => Sieve p f | p where
+  sieve : p a b -> a -> f b
+
+
+public export
+interface (Profunctor p, Functor f) => Cosieve p f | p where
+  cosieve : p a b -> f a -> b