theorem
  for G,f1,f2 st 2 <= len f1 & 2 <= len f2 & f1 is_sequence_on G & f2
  is_sequence_on G & f1/.1 in rng Line(G,1) & f1/.len f1 in rng Line(G,len G) &
f2/.1 in rng Col(G,1) & f2/.len f2 in rng Col(G,width G) holds L~f1 meets L~f2
  by Th2;
