reserve a,b,c,h for Integer;
reserve k,m,n for Nat;
reserve i,j,z for Integer;
reserve p for Prime;

theorem Th82:
  card (multiples(2) /\ {a,a+1}) = 1
  proof
    multiples(2) /\ {a,a+1} = {a} or multiples(2) /\ {a,a+1} = {a+1}
    by Th79,Th80;
    hence thesis by CARD_1:30;
  end;
