
theorem Rascal 1 = <*1,1*>
  proof
    reconsider f = Rascal 1 as (1+1)-element FinSequence;
    dom f = Seg (1 + 1) by Def1; then
    1 in dom f & 2 in dom f; then
    f.1 = (1-1)*(1+1-1) + 1 &
    f.2 = (2-1)*(1+1-2) + 1 by Def1;
    hence thesis;
  end;
