If true, the following conjecture of Thomassen [Th81] is a planarity criterion for a special class of graphs that involves only K 5. Recall that a planar graph on n vertices contains at most 3n-6 ...

A quadratic equation is drawn as a curve on a set of axes. This type of curve is called a parabola and it is symmetrical. To draw the graph we need coordinates. We generate these coordinates by ...