Questions tagged [hilbert-symbol]

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Hilbert symbol over 2-adic field

Let $F$ be a finite extension of $\mathbb{Q}_2$, and let $(-,-)_F$ be the quadratic Hilbert symbol over $F$. Is the following true? $(-1,-1)_F=1$ if and only if $\sqrt{-1}\in F$
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5 votes
1 answer
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Relation in Brauer group coming from trace form

Let $L/K$ be a cubic (or, more generally, odd-order) extension of fields of characteristic $0$. To every element $a \in L^\times$ we can associate the quadratic form \begin{align*} q_a : L &\to K \...
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4 votes
1 answer
490 views

Hilbert Symbols, Norms, and p-adic roots of unity

Let $p$ be an odd prime number, let $\mathbb{Q}_p$ be the field of $p$-adic numbers, and let $\overline{\mathbb{Q}_p}$ be an algebraic closure of it. For a primitive $p$-th root of unity $\zeta_p \in ...
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10 votes
1 answer
576 views

Dyadic Hilbert symbols and higher unit groups

Let $F$ be a local dyadic number field, $\mathfrak{p}$ its maximal ideal, $(*,*)_F$ its quadratic Hilbert symbol and $e$ its ramification index (i.e. $\mathfrak{p}^e$ is exact divisor of $2$). Fix an ...
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7 votes
1 answer
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Hilbert symbol averages

Let me call a pair of integers $a, b$ acceptable if the equation $ax^2 + by^2 = z^2$ has a non-trivial rational solution. Theorem 4.5.4 of Cojocaru-Murty's book on Sieves says that the number of ...
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0 votes
1 answer
118 views

Norm Residue Symbol refinement?

From Wikipedia: given $a\in K^\times$, (a,b)=1 for all b [in K*] if and only if a is in K*ⁿ So suppose that $(\frac{a\ ,\ K^\times\!}{p})\neq 1$ [assume $n$ above ...
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1 vote
0 answers
145 views

Skew symmetry for the Hilbert symbol

Let $K$ be a local field containing the group $\mu_n$ of $n$th roots of 1 and the $\theta_K:K^*\to G_K^{ab}$ be the reciprocity map. The we know that the Hilbert symbol $$K^*\times K^*\to \mu_n$$ $$(a,...
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11 votes
1 answer
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Weil reciprocity vs Artin reciprocity

This is probably an easy question for the experts: Given two rational functions $f$, $g$ on a non-singular projective algebraic curve X (over an algebraically closed field $k$) and $p \in X$, one ...
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9 votes
0 answers
562 views

Hilbert symbol and Weil index, beyond the quadratic case?

Let $F$ be a local nonarchimedean field. Let $n$ be a positive integer for which the group $\mu_n(F)$ of $n^{th}$ roots of unity in $F$ has order $n$. Let $\epsilon: \mu_n(F) \rightarrow C^\times$ ...
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