Most general higher-order constraint describing a sequence of integers ordered with respect to a relation n CLP(FD), we frequently need to state: "This is a list of integers and finite domain variables in (sometimes: strictly) ascending/descending order." Is there any CLP(FD) system that provides a general (parametrisable) built-in constraint for this task? SWI-Prolog provides a constraint called chain/2, which is similar to what I am looking for. However, the name is slightly too specific to encompass all relations that the constraint can describe (example: #< is not a partial order but admissible in chain/2, leading to the sequence — taken as a set of integers — no longer counting as a chain as defined in mathematical order-theory). Hence, the name does not fully describe what the constraint actually implements. Please give the most general definition with respect to the usual binary CLP(FD) constraints — or a suitable subset that contains at least #<, #>, #=< and #>= — including the proper name according to the algebraic structure the constraint defines. The condition imposed is that the constraint describe an actual mathematical structure that has a proper name in the literature. As a start, consider with SICStus Prolog or SWI: