Abscissa and ordinate is the distance between the projection and the origin of the axis, and whose sign is given by the location on the projection relative to the origin (before: negative; after: positive). Usually these are the horizontal and vertical coordinates of a point in a two-dimensional rectangular Cartesian coordinate system. The terms can also refer to the horizontal and vertical axes respectively (typically "x"-axis and "y"–axis) of a two-dimensional graph. An ordered pair consists of two terms—the abscissa (horizontal, usually "x") and the ordinate (vertical, usually "y")—which define the location of a point in two-dimensional rectangular space. Though the word "abscissa"
Complement graph the one for simple graphs, since applying it to a graph with no self-loops would result in a graph with self-loops on all vertices. Several graph-theoretic concepts are related to each other via complement graphs: A self-complementary graph is a graph that is isomorphic to its own complement. Examples include the four-vertex path graph and five-vertex cycle graph. Several classes of graphs are self-complementary, in the sense that the complement of any graph in one of these classes is another graph in the same class. In the analysis of algorithms on graphs, the distinction between a graph and its complement