reserve GS for GraphStruct;
reserve G,G1,G2,G3 for _Graph;
reserve e,x,x1,x2,y,y1,y2,E,V,X,Y for set;
reserve n,n1,n2 for Nat;
reserve v,v1,v2 for Vertex of G;

theorem Th143:
  for G being _Graph, v being Vertex of G, e,w being object
  st v is isolated holds not e Joins v,w,G by Th62;
