HighlightedEdgeStyle is an option to Highlight that determines how the highlighted edges are drawn.

HighlightedVertexColors is an option to Highlight that determines which colors are used for the highlighted vertices.

HighlightedVertexStyle is an option to Highlight that determines how the highlighted vertices are drawn.

Highlight[g, p] displays g with elements in p highlighted. The second argument p has the form {s_1, s_2, ...}, where the s_i are disjoint subsets of vertices and edges of g.

Hypercube[n] constructs an n-dimensional hypercube.

IcosahedralGraph returns the graph corresponding to the icosahedron, a Platonic solid.

IdenticalQ[g, h] yields True if graphs g and h have identical edge lists, even though the associated graphics information need not be the same.

IdentityPermutation[n] gives the size-n identity permutation.

IncidenceMatrix[g] returns the (0, 1)-matrix of graph g, which has a row for each vertex and a column for each edge and (v, e) = 1 if and only if vertex v is incident upon ...

InDegree[g, n] returns the in-degree of vertex n in directed graph g. InDegree[g] returns the sequence of in-degrees of the vertices in directed graph g.