degreeVertex -- returns the degree of a vertex

Synopsis

• Usage:

  d = degreeVertex(H,n)

  d = degreeVertex(H,V)

• Inputs:
  • H, a hypergraph,
  • n, an integer, the index of a vertex
  • V, a ring element, a vertex/variable of the HyperGraph
• Outputs:
  • d, an integer, the degree of vertex V (or vertex number n)

Description

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

i2 : k5 = completeGraph S

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

o2 : Graph

i3 : dv = degreeVertex(k5,a)

o3 = 4

i4 : n = neighbors(k5,a)

o4 = {b, c, d, e}

o4 : List

i5 : #n == dv

o5 = true

i6 : degreeVertex(k5,2)

o6 = 4

i7 : h = hyperGraph {a*b*c,c*d,a*d*e,b*e,c*e}

o7 = HyperGraph{edges => {{a, b, c}, {c, d}, {b, e}, {c, e}, {a, d, e}}}
                ring => S
                vertices => {a, b, c, d, e}

o7 : HyperGraph

i8 : degreeVertex(h,a)

o8 = 2

i9 : degreeVertex(h,2) -- degree of c

o9 = 3

See also

• neighbors -- returns the neighbors of a vertex or list of vertices
• vertices(HyperGraph) -- gets the vertices of a (hyper)graph