| The paper first establishes
the order of magnitude of maximal sets, S, of residues (  mod p) so that the sums of
different numbers of elements are distinct.
    In the second part irrationalities of Lambert Series of the form ∑
f(n)∕α1⋯an are
obtained where f(n) = d(n),σ(n) or φ(n) and the ai are integers, ai ≧ 2, which
satisfy suitable growth conditions. |