data Graph (a : Type) where
    EmptyG  : Graph a
  ; Vertex  : a -> Graph a
  ; Overlay : Graph a -> Graph a -> Graph a
  ; Connect : Graph a -> Graph a -> Graph a

vertices : forall {a : Type} 
         . List a -> Graph a

edge : forall {a : Type} 
     . a -> a -> Graph a

mapG : forall {a : Type, b : Type} 
     . (a -> b) [0..∞] -> Graph a -> Graph b

foldG : forall {a : Type, b : Type} 
      . b [0..∞] -> (a -> b) [0..∞] -> (b -> b -> b) [0..∞] -> (b -> b -> b) [0..∞] -> Graph a -> b

isEmpty : forall {a : Type} 
        . Graph (a [0]) -> Bool

hasVertex : Int [0..∞] -> Graph Int -> Bool

toList : forall {a : Type} 
       . Graph a -> List a

transpose : forall {a : Type} 
          . Graph a -> Graph a

add : Int -> Int -> Int

size : forall {a : Type} 
     . Graph (a [0]) -> Int

vertexcount : forall {a : Type} 
            . Graph (a [0]) -> Int