theorem Th11:
  primesFinS 3 = <*2,3,5*>
  proof
    set f = primesFinS 3;
A1: len f = 3 by Def1;
    f.(0+1) = 2 & f.(1+1) = 3 & f.(2+1) = 5 by Def1,MOEBIUS2:8,10,12;
    hence thesis by A1,FINSEQ_1:45;
  end;
