 reserve n,i,k,m for Nat;
 reserve p for Prime;
 reserve s, s1, s2 for Real_Sequence;

theorem
  ReciProducts 2 = { 1 / 2, 1 }
  proof
    Sgm {2} = <*2*> by FINSEQ_3:44; then
A2: 1 / Product Sgm {2} = 1 / 2 by RVSUM_1:95;
    {2} c= SetPrimes 2 by Set2; then
S1: 1 / 2 in ReciProducts 2 by A2;
A4: Product Sgm {} = 1 by RVSUM_1:94,FINSEQ_1:51;
Z1: {} c= SetPrimes 2;
    1 / Product Sgm {} = 1 by A4; then
    1 in ReciProducts 2 by Z1; then
ZZ: { 1 / 2, 1 } c= ReciProducts 2 by ZFMISC_1:32,S1;
    ReciProducts 2 c= {1 / 2, 1}
    proof
      let x be object;
      assume x in ReciProducts 2; then
      consider X being Subset of SetPrimes 2 such that
N1:   x = 1 / Product Sgm X;
      X = {} or X = {2} by ZFMISC_1:33,Set2;
      hence thesis by TARSKI:def 2,N1,A4,A2;
    end;
    hence thesis by TARSKI:2,ZZ;
  end;
