are used to locate a person's position. For locating position in the continuum there are almost as many systems as there are means of travel. However, I find a short series of three values useful from a general point of view. In this view, koph is a realm's position between the infinite extremes of Amber and Chaos and corresponds to the 'Quantum Number' of GURPS Time Travel. Sigma is the arc occupied by a realm within its koph slice. Aleph is the distance from the realm to the direct line between Amber and Chaos.