let G2 be _Graph; for v being object
for V being Subset of (the_Vertices_of G2)
for G1 being addAdjVertexAll of G2,v,V st not v in the_Vertices_of G2 holds
not G1 is loopfull
let v be object ; for V being Subset of (the_Vertices_of G2)
for G1 being addAdjVertexAll of G2,v,V st not v in the_Vertices_of G2 holds
not G1 is loopfull
let V be Subset of (the_Vertices_of G2); for G1 being addAdjVertexAll of G2,v,V st not v in the_Vertices_of G2 holds
not G1 is loopfull
let G1 be addAdjVertexAll of G2,v,V; ( not v in the_Vertices_of G2 implies not G1 is loopfull )
assume A1:
not v in the_Vertices_of G2
; not G1 is loopfull
then reconsider v = v as Vertex of G1 by GLIB_007:50;
for e being object holds not e Joins v,v,G1
by A1, GLIB_007:def 4;
hence
not G1 is loopfull
; verum