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Theorems implying the non-vanishing of $$\sum \chi(m)m^{-1}$$ for real residue-characters. (English) Zbl 0228.10021

##### MSC:
 11M20 Real zeros of $$L(s, \chi)$$; results on $$L(1, \chi)$$ 11L40 Estimates on character sums 11N13 Primes in congruence classes