# isEdge -- determines if an edge is in a (hyper)graph

## Synopsis

• Usage:
b = isEdge(H,E)
b = isEdge(H,M)
• Inputs:
• H, ,
• E, a list, of vertices
• M, , a monomial representing an edge
• Outputs:
• b, , true iff E (or support M) is an edge of H

## Description

This function checks if a given edge, represented either as a list or monomial, belongs to a given (hyper)graph.

 i1 : S = QQ[z_1..z_8]; i2 : h = hyperGraph {z_2*z_3*z_4,z_6*z_8,z_7*z_5,z_1*z_6*z_7,z_2*z_4*z_8}; i3 : edges h o3 = {{z , z , z }, {z , z }, {z , z , z }, {z , z , z }, {z , z }} 2 3 4 5 7 1 6 7 2 4 8 6 8 o3 : List i4 : isEdge (h,{z_2,z_4,z_8}) o4 = true i5 : isEdge (h,z_2*z_3*z_4) o5 = true i6 : isEdge (h,{z_1,z_2}) o6 = false