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
  for G1 being _finite _Graph, G2 being Subgraph of G1
  holds G2 is spanning iff G1.order() = G2.order() by CARD_2:102;
