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6 votes
1 answer
563 views

Is decomposability of integer polynomials over the rational numbers an undecidable problem?

By a decomposition of a polynomial $F(x)$ over a field $K$ we mean writing $F(x)$ as $$ F(x)=G(H(x)) \quad(G(x), H(x) \in K[x]), $$ which is nontrivial if $\operatorname{deg} G(x)>1$ and $\...
SARTHAK GUPTA's user avatar
2 votes
0 answers
120 views

Polynomial discriminant equation

This is a fairly straightforward question, and I am hoping a definitive answer exists. Does there exist a quadratic form $A \in \mathbb{C}[x_1, x_2, x_3, x_4]$ and a cubic form $B \in \mathbb{C}[x_1, ...
Stanley Yao Xiao's user avatar
3 votes
0 answers
131 views

Galois cohomology and Levi subgroups

Let $F$ a field and $G$ a smooth connected reductive group with a Levi subgroup $M$. Under what assumptions is $H^1(F, M) \to H^1(F, G)$ injective? In the case $F$ is nonarchimedean local I believe ...
C.D.'s user avatar
  • 605
1 vote
0 answers
66 views

Hasse principle for Brauer groups of fields of transcendence degree 2

In his paper "A Hasse principle for function fields over PAC fields" (DOI link), Ido Efrat proves the following result: Let $F$ be an extension of a perfect PAC field $K$ of relative ...
aspear's user avatar
  • 41