isolatedVertices -- returns all vertices not contained in any edge

i1 : R = QQ[a,b,c,d,e];

i2 : G = graph {a*b,c*d}

o2 = Graph{edges => {{a, b}, {c, d}}  }
           ring => R
           vertices => {a, b, c, d, e}

o2 : Graph

i3 : isolatedVertices G

o3 = {e}

o3 : List

i4 : H = hyperGraph {a*b,c}

o4 = HyperGraph{edges => {{a, b}, {c}}     }
                ring => R
                vertices => {a, b, c, d, e}

o4 : HyperGraph

i5 : isolatedVertices H

o5 = {d, e}

o5 : List