UnrankSubset[n, l] gives the n\[Null]^th subset of list l, listed in some canonical order.
UnweightedQ[g] yields True if all edge weights are 1 and False otherwise.
UpperLeft is a value that options VertexNumberPosition, VertexLabelPosition, and EdgeLabelPosition can take on in ShowGraph.
UpperRight is a value that options VertexNumberPosition, VertexLabelPosition, and EdgeLabelPosition can take on in ShowGraph.
VertexCoverQ[g, c] yields True if the vertices in list c define a vertex cover of graph g.
V
(Combinatorica Package Symbol) V[g] gives the order or number of vertices of the graph g.
WaltherGraph returns the Walther graph.
WeaklyConnectedComponents[g] gives the weakly connected components of directed graph g as lists of vertices.
New function HornerForm has been added to the built-in Mathematica kernel.
Some of the functionality in Graphics`Spline` has been added to the built-in Mathematica kernel.