reserve p,q,r for FinSequence,
  x,y for object;

theorem Th45:
  for R being Relation, a,b being object st
  a,b are_divergent<=1_wrt R holds a,b are_divergent_wrt R
proof
  let R be Relation, a,b be object;
  given c being object such that
A1: ([c,a] in R or a = c) & ([c,b] in R or b = c);
  take c;
  thus thesis by A1,Th12,Th15;
end;
