adamc@1180: con incl :: K --> {K} -> {K} -> Type
adamc@1180: 
adamc@1180: val incl : K --> r1 :: {K} -> r2 :: {K} -> [r1 ~ r2] => incl r1 (r1 ++ r2)
adamc@1180: val proj : r1 ::: {Type} -> r2 ::: {Type} -> incl r1 r2 -> $r2 -> $r1
adamc@1180: 
adamc@1182: val inv1 : K --> nm :: Name -> t :: K -> r :: {K} -> r' :: {K}
adamc@1180:            -> [[nm] ~ r] =>
adamc@1180:     f :: (Name -> K -> {K} -> Type)
adamc@1180:     -> incl ([nm = t] ++ r) r'
adamc@1180:     -> (nm :: Name -> t :: K -> r :: {K} -> [[nm] ~ r] => f nm t ([nm = t] ++ r))
adamc@1180:     -> f nm t r'
adamc@1181: val inv2 : K --> nm :: Name -> t :: K -> r :: {K} -> r' :: {K}
adamc@1180:            -> [[nm] ~ r] =>
adamc@1180:     incl ([nm = t] ++ r) r' -> incl r r'
adamc@1180: 
adamc@1180: val fold : K --> tf :: ({K} -> Type) -> r ::: {K}
adamc@1180:            -> (nm :: Name -> v :: K -> r' :: {K}
adamc@1180:                -> [[nm] ~ r'] => incl ([nm = v] ++ r') r -> tf r' -> tf ([nm = v] ++ r'))
adamc@1180:            -> tf []
adamc@1180:            -> folder r -> tf r