Add UpdateFunction and DomainMapping.

networks.rkt

@@ -5,9 +5,11 @@
            typed/graph racket/random)
 
   (provide
-   State)
+   State UpdateFunction DomainMapping)
 
   (define-type (State a) (VariableMapping a))
+  (define-type (UpdateFunction a) (-> (State a) a))
+  (define-type (DomainMapping a) (VariableMapping (Listof a)))
   )
 
 (require 'typed)

scribblings/networks.scrbl

@@ -34,6 +34,20 @@ the variables.  A synonym of @racket[VariableMapping].
 
 }
 
+@defform[(UpdateFunction a)]{
+
+An update function is a function computing a value from the given
+state.  This is a synonym of the type @racket[(-> (State a) a)].
+
+}
+
+@defform[(DomainMapping a)]{
+
+A domain mapping is a hash table mapping variables to the lists of values in
+their domains.
+
+}
+
 @section{Syntactic description of networks}
 
 @section{Inferring interaction graphs}