
theorem Th50:
for G being SimpleGraph, x being set st x in Vertices G
 holds { {}, {x} } is Clique of G
proof
 let G be SimpleGraph, x be set such that
A1: x in Vertices G;
   set C = CompleteSGraph {x};
A2: C = { {}, {x} } by Th36;
 thus { {}, {x} } is Clique of G by A2,A1,Th39;
end;
