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"
Graph minor apply this result constructively, it is necessary to know what the forbidden minors of the graph family are. In some cases, the forbidden minors are known, or can be computed. In the case where "H" is a fixed planar graph, then we can test in linear time in an input graph "G" whether "H" is a minor of "G". In cases where "H" is not fixed, faster algorithms are known in the case where "G" is planar. Graph minor In graph theory, an undirected graph "H" is called a minor of the graph "G" if "H" can be formed from