let remove_itv _fuzzy_order (start,stop as ss) to_ =
let concerned_intervals =
concerned_intervals Int_Interv.fuzzy_order ss to_ in
List.fold_left
(fun acc (bi,ei as i,vv) ->
let r = remove i acc in
let r = if Int.lt bi start then add (bi,Int.pred start) vv r
else r
in let r = if Int.gt ei stop then add (Int.succ stop,ei) vv r
else r
in r)
to_ concerned_intervals