Circuit de Monaco downhill again to a double right-hander called "Portier," named after region of Monaco, before heading into the famous tunnel, a unique feature of a Formula One circuit. (Until 2009 only one other circuit, Detroit in 1982–88, featured a tunnel, but the F1 series now includes racing at the Yas Marina Circuit in Abu Dhabi, which presents a shorter tunnel at the exit of the pit lane.) As well as the change of light making visibility poor, a car can lose 20–30% of its downforce due to the unique aerodynamic properties of the tunnel. The tunnel also presents a unique problem
Circuit rank of any planar graph with the same vertex set, is called the meshedness coefficient. For a connected planar graph with edges and vertices, the meshedness coefficient can be computed by the formula Here, the numerator formula_5 of the formula is the circuit rank of the given graph, and the denominator formula_6 is the largest possible circuit rank of an -vertex planar graph. The meshedness coefficient ranges between 0 for trees and 1 for maximal planar graphs. The circuit rank controls the number of ears in an ear decomposition of a graph, a partition of the edges of the graph into