# Does normal Riemann hypothesis follow from extended Riemann hypothesis

Does normal Riemann hypothesis for $\zeta_{\mathbb{Q}}$ follows from the extended Riemann hypothesis for some $K \neq \mathbb{Q}$ (i.e. the statement that all zeroes of the Dedekind zeta function $\zeta_K$ for $K$ a number field in the critical strip lie on the axis $\mathfrak{R}(s)=1/2$)?

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Well, $\mathbb{Q}$ is a number field... –  Qiaochu Yuan Aug 18 '12 at 0:12
Yes I mean if we know it is true for one $K \neq \mathbb{Q}$ does it follow for $\mathbb{Q}$? –  user16974 Aug 18 '12 at 0:13
Yes, certainly: zeta functions of abelian extensions of $\mathbb Q$ factor as products of Dirichlet $L$-functions over $\mathbb Q$, including $\zeta(s)$, and those other $L$-functions have no poles (which might cancel an off-line zero of zeta), so RH for any abelian extension of $\mathbb Q$ implies that for $\mathbb Q$.
At this point in history, the fact that we do not know that all Artin $L$-functions lack poles in the critical strip severely complicates our provable understanding of an analogous assertion for not-abelian extensions.