Stochastic programs with dominance contraints induced by mixed-integer linear recourse.

The specification discloses a tone changer for a guitar (12) having a multiple pull actuator mechanism (14). One or more of the guitar strings are tightened in response to pulling a lever arm (22) away from the guitar (12), or by pushing the lever arm (30) towards the guitar (12), or by pulling the lever arm (26) upwardly in a rotational plane parallel to the rear side of the guitar (12). Straps (16) and (18) are connected between the lever arms (22) and (26), respectively, and are connected at their other end to the performer for selectively imparting an appropriate force on the lever arms. An extension arm (32) is connected to the lever arm (30) for engaging the performer to push the lever arm inwardly towards the guitar (12).