"Imagine throwing a dart at a dart board, miles away, with a blindfold on, trying to hit the bullseye." ~ SemThe Point of Reference Problem is the theoretical problem which prevents the ARC from connecting to any one specific world in order to send a lost traveler home from Asphodel back to their home world. The problem is the result of having no one clear reference point in the multi-verse or subspace for which the ARC can calibrate from, allowing the miracle machine the ability to distinguish one world out of an infinite number.
Described as looking at an abstract painting without the artists own context behind its creation, the Point of Reference Problem remains the sole reason why Sem, Otto, and Erland have all failed in finding a way to send lost travelers back to where they came from. Although solutions have been tested, all have failed except for the famous One Way Ticket equation.
One Way Ticket Equation
Unable to find the one reusable equation to send lost travelers home, Erland developed the One Way Ticket equation as the only foreseen method of sending a traveler home. The manner in which the equation solves the Point of Reference Problem is by using the individual themselves as the point of reference the ARC needs to send them home, there for binding the ARC to one world indefinitely and leaving it useless to those left behind in Asphodel. This equation was once almost used by Erland. However, after a brief argument between him and his partner, Marie, he chose not to use it as the result would mean stranding everyone in Asphodel forever. With no other choice, he kept the equation a secret between Marie and himself, and turned his efforts towards creating the Guardian Project.
The equation was eventually discovered by Sem during his meeting in the ice cave with Erland as the visage bound to the Soul of the Cosmos. After which, Sem used the equation on Ally to prevent her from being harmed by the mob of Alpha Rioters and as a way to prevent everyone from leaving.