Abscissa and ordinate a parametric equation. Used in this way, the abscissa can be thought of as a coordinate-geometry analog to the independent variable in a mathematical model or experiment (with any ordinates filling a role analogous to dependent variables). Abscissa and ordinate In mathematics, the abscissa (; plural "abscissae" or "abscissæ" or "abscissas") and the ordinate are respectively the first and second coordinate of a point in a coordinate system. The abscissa of a point is the signed measure of its projection on the primary axis, whose absolute value is the distance between the projection and the origin of the axis, and
Shannon capacity of a graph The Lovász number ϑ("G") is a different graph invariant, that can be computed numerically to high accuracy in polynomial time by an algorithm based on the ellipsoid method. The Shannon capacity of a graph "G" is bounded from below by α("G"), and from above by ϑ("G"). In some cases, ϑ("G") and the Shannon capacity coincide; for instance, for the graph of a pentagon, both are equal to . However, there exist other graphs for which the Shannon capacity and the Lovász number differ. Haemers provided another upper bound on the Shannon capacity, which is sometimes better than Lovász bound: where