Skip to main content
another correction (thanks Chandan)
Source Link
David Loeffler
  • 37k
  • 3
  • 89
  • 194

Let $F$ be an unramified extension of $\mathbf{Q}_p$ of degree $n$, and let $K = F(\alpha)$ where $\alpha$ satisfies $\alpha^{p^n - 1} = -p$.

I'm interested in the local $\varepsilon$-factors attached to finite-order characters of the Galois group of $G_k = \operatorname{Gal}(K(\mu_{p^k}) / F)$, for $k \gg 0$. Specifically, I'd like to know if there's any relation between these $\varepsilon$-factors and the quantities $$ \tau(u, \omega) = \sum_{g \in G_k} \omega(g)^{-1} g(u) $$ for suitable $u \in K(\mu_{p^k})$. If $n = 1$, so $K = F = \mathbf{Q}_p$$F = \mathbf{Q}_p$ and $K=\mathbf{Q}_p(\mu_p)$, then $\tau(u, \omega)$ for $u = \zeta_{p^k}$ is just a Gauss sum, and it's well known that these are the epsilon-factors. Can one say anything useful for $n \ge 2$?

Let $F$ be an unramified extension of $\mathbf{Q}_p$ of degree $n$, and let $K = F(\alpha)$ where $\alpha$ satisfies $\alpha^{p^n - 1} = -p$.

I'm interested in the local $\varepsilon$-factors attached to finite-order characters of the Galois group of $G_k = \operatorname{Gal}(K(\mu_{p^k}) / F)$, for $k \gg 0$. Specifically, I'd like to know if there's any relation between these $\varepsilon$-factors and the quantities $$ \tau(u, \omega) = \sum_{g \in G_k} \omega(g)^{-1} g(u) $$ for suitable $u \in K(\mu_{p^k})$. If $n = 1$, so $K = F = \mathbf{Q}_p$, then $\tau(u, \omega)$ for $u = \zeta_{p^k}$ is just a Gauss sum, and it's well known that these are the epsilon-factors. Can one say anything useful for $n \ge 2$?

Let $F$ be an unramified extension of $\mathbf{Q}_p$ of degree $n$, and let $K = F(\alpha)$ where $\alpha$ satisfies $\alpha^{p^n - 1} = -p$.

I'm interested in the local $\varepsilon$-factors attached to finite-order characters of the Galois group of $G_k = \operatorname{Gal}(K(\mu_{p^k}) / F)$, for $k \gg 0$. Specifically, I'd like to know if there's any relation between these $\varepsilon$-factors and the quantities $$ \tau(u, \omega) = \sum_{g \in G_k} \omega(g)^{-1} g(u) $$ for suitable $u \in K(\mu_{p^k})$. If $n = 1$, so $F = \mathbf{Q}_p$ and $K=\mathbf{Q}_p(\mu_p)$, then $\tau(u, \omega)$ for $u = \zeta_{p^k}$ is just a Gauss sum, and it's well known that these are the epsilon-factors. Can one say anything useful for $n \ge 2$?

corrected gamma to g
Source Link
David Loeffler
  • 37k
  • 3
  • 89
  • 194

Let $F$ be an unramified extension of $\mathbf{Q}_p$ of degree $n$, and let $K = F(\alpha)$ where $\alpha$ satisfies $\alpha^{p^n - 1} = -p$.

I'm interested in the local $\varepsilon$-factors attached to finite-order characters of the Galois group of $G_k = \operatorname{Gal}(K(\mu_{p^k}) / F)$, for $k \gg 0$. Specifically, I'd like to know if there's any relation between these $\varepsilon$-factors and the quantities $$ \tau(u, \omega) = \sum_{\gamma \in G_k} \omega(g)^{-1} g(u) $$$$ \tau(u, \omega) = \sum_{g \in G_k} \omega(g)^{-1} g(u) $$ for suitable $u \in K(\mu_{p^k})$. If $n = 1$, so $K = F = \mathbf{Q}_p$, then $\tau(u, \omega)$ for $u = \zeta_{p^k}$ is just a Gauss sum, and it's well known that these are the epsilon-factors. Can one say anything useful for $n \ge 2$?

Let $F$ be an unramified extension of $\mathbf{Q}_p$ of degree $n$, and let $K = F(\alpha)$ where $\alpha$ satisfies $\alpha^{p^n - 1} = -p$.

I'm interested in the local $\varepsilon$-factors attached to finite-order characters of the Galois group of $G_k = \operatorname{Gal}(K(\mu_{p^k}) / F)$, for $k \gg 0$. Specifically, I'd like to know if there's any relation between these $\varepsilon$-factors and the quantities $$ \tau(u, \omega) = \sum_{\gamma \in G_k} \omega(g)^{-1} g(u) $$ for suitable $u \in K(\mu_{p^k})$. If $n = 1$, so $K = F = \mathbf{Q}_p$, then $\tau(u, \omega)$ for $u = \zeta_{p^k}$ is just a Gauss sum, and it's well known that these are the epsilon-factors. Can one say anything useful for $n \ge 2$?

Let $F$ be an unramified extension of $\mathbf{Q}_p$ of degree $n$, and let $K = F(\alpha)$ where $\alpha$ satisfies $\alpha^{p^n - 1} = -p$.

I'm interested in the local $\varepsilon$-factors attached to finite-order characters of the Galois group of $G_k = \operatorname{Gal}(K(\mu_{p^k}) / F)$, for $k \gg 0$. Specifically, I'd like to know if there's any relation between these $\varepsilon$-factors and the quantities $$ \tau(u, \omega) = \sum_{g \in G_k} \omega(g)^{-1} g(u) $$ for suitable $u \in K(\mu_{p^k})$. If $n = 1$, so $K = F = \mathbf{Q}_p$, then $\tau(u, \omega)$ for $u = \zeta_{p^k}$ is just a Gauss sum, and it's well known that these are the epsilon-factors. Can one say anything useful for $n \ge 2$?

Source Link
David Loeffler
  • 37k
  • 3
  • 89
  • 194

Epsilon factors for tamely ramified extensions of local fields

Let $F$ be an unramified extension of $\mathbf{Q}_p$ of degree $n$, and let $K = F(\alpha)$ where $\alpha$ satisfies $\alpha^{p^n - 1} = -p$.

I'm interested in the local $\varepsilon$-factors attached to finite-order characters of the Galois group of $G_k = \operatorname{Gal}(K(\mu_{p^k}) / F)$, for $k \gg 0$. Specifically, I'd like to know if there's any relation between these $\varepsilon$-factors and the quantities $$ \tau(u, \omega) = \sum_{\gamma \in G_k} \omega(g)^{-1} g(u) $$ for suitable $u \in K(\mu_{p^k})$. If $n = 1$, so $K = F = \mathbf{Q}_p$, then $\tau(u, \omega)$ for $u = \zeta_{p^k}$ is just a Gauss sum, and it's well known that these are the epsilon-factors. Can one say anything useful for $n \ge 2$?