:: deftheorem Def30 defines .edgesBetween GLIB_000:def 30 :
for G being _Graph
for X, Y being set
for b₄ being Subset of (the_Edges_of G) holds
( b₄ = G .edgesBetween (X,Y) iff for e being object holds
( e in b₄ iff e SJoins X,Y,G ) );