:: deftheorem defines Joins GLIB_000:def 13 :
for G being _Graph
for x, y, e being object holds
( e Joins x,y,G iff ( e in the_Edges_of G & ( ( (the_Source_of G) . e = x & (the_Target_of G) . e = y ) or ( (the_Source_of G) . e = y & (the_Target_of G) . e = x ) ) ) );