reserve k,n,m for Nat,
  a,x,X,Y for set,
  D,D1,D2,S for non empty set,
  p,q for FinSequence of NAT;
reserve F,F1,G,G1,H,H1,H2 for LTL-formula;
reserve sq,sq9 for FinSequence;

theorem
  F is atomic implies not H is_immediate_constituent_of F
proof
  assume F is atomic;
  then F.1 <> 2 & F.1 <> 3 & F.1 <> 4 & F.1 <> 5 & F.1 <> 0 & F.1 <> 1 by Lm9;
  hence thesis by Th12;
end;
