ReflexiveQ[g] yields True if the adjacency matrix of g represents a reflexive binary relation.

RegularGraph[k, n] constructs a semirandom k-regular graph on n vertices, if such a graph exists.

RegularQ[g] yields True if g is a regular graph.

RemoveMultipleEdges[g] returns the graph obtained by deleting multiple edges from g.

RemoveSelfLoops[g] returns the graph obtained by deleting self-loops in g.

ResidualFlowGraph[g, flow] returns the directed residual flow graph for graph g with respect to flow.

RevealCycles[p] unveils the canonical hidden cycle structure of permutation p.

ReverseEdges[g] flips the directions of all edges in a directed graph.

RGFQ[l] yields True if l is a restricted growth function. It yields False otherwise.

RGFs[n] lists all restricted growth functions on the first n natural numbers in lexicographic order.