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
Line graph of a hypergraph graph.). In hypergraph theory, it is often natural to require that hypergraphs be "k"-uniform. Every graph is the line graph of some hypergraph, but, given a fixed edge size "k", not every graph is a line graph of some "k"-uniform hypergraph. A main problem is to characterize those that are, for each "k" ≥ 3. A hypergraph is linear if each pair of hyperedges intersects in at most one vertex. Every graph is the line graph, not only of some hypergraph, but of some linear hypergraph . characterized line graphs of graphs by a list of 9 forbidden induced subgraphs.