extractPTermNames (PApp _ p pas)     = let names = concatMap extractPArg pas
                                       in  (extract p) ++ names
extractPTermNames (PApp _ p pas)     = let names = concatMap extractPArg pas
                                       in  (extract p) ++ names
extractPTermNames (PApp _ p pas)     = let names = concatMap extractPArg pas
                                       in  (extract p) ++ names