mapStartTerms :: Ord f' => (f -> f') -> StartTerms f -> StartTerms f'
mapStartTerms f (AllTerms fs)      = AllTerms (f `S.map` fs)
mapStartTerms :: Ord f' => (f -> f') -> StartTerms f -> StartTerms f'
mapStartTerms f (AllTerms fs)      = AllTerms (f `S.map` fs)
mapStartTerms f (AllTerms fs)      = AllTerms (f `S.map` fs)