--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mem.urs	Tue Dec 14 09:49:10 2010 -0500
@@ -0,0 +1,15 @@
+(** A record membership predicate *)
+
+con mem :: K --> Name -> K -> {K} -> Type
+
+val mem : K --> nm :: Name -> t :: K -> r :: {K} -> [[nm] ~ r] => mem nm t ([nm = t] ++ r)
+val mp : K --> K2 --> f :: (K -> K2) -> nm ::: Name -> t ::: K -> r ::: {K} -> mem nm t r -> mem nm (f t) (map f r)
+
+val proj : nm ::: Name -> t ::: Type -> r ::: {Type} -> mem nm t r -> $r -> t
+val replace : nm ::: Name -> t ::: Type -> r ::: {Type} -> mem nm t r -> $r -> t -> $r
+
+val fold : K --> tf :: ({K} -> Type) -> r ::: {K}
+           -> (nm :: Name -> v :: K -> r' :: {K} -> [[nm] ~ r']
+               => mem nm v r -> tf r' -> tf ([nm = v] ++ r'))
+           -> tf []
+           -> folder r -> tf r