:: deftheorem Def6 defines SubgraphRel GLENUM00:def 6 :
for G being _Graph
for b₂ being Relation of (G .allSG()) holds
( b₂ = SubgraphRel G iff for H1, H2 being Element of G .allSG() holds
( [H1,H2] in b₂ iff H1 is Subgraph of H2 ) );