Hyperbolicity and near hyperbolicity of quadratic forms over function fields of quadrics

被引:2
|
作者
Scully, Stephen [1 ]
机构
[1] Univ Alberta, Dept Math & Stat Sci, Edmonton, AB T6G 2G1, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
DESCENT PROBLEM; WITT KERNELS;
D O I
10.1007/s00208-018-1705-9
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
Let p and q be anisotropic quadratic forms over a field F of characteristic not equal 2, let s be the unique non-negative integer such that 2(s) < dim(p) <= 2(s+1), and let k denote the dimension of the anisotropic part of q after scalar extension to the function field F(p) of p. We conjecture that the dimension of q must lie within k of an integer multiple of 2(s+1). This can be viewed as a direct generalization of Hoffmann's Separation theorem. Among other cases, we prove that the conjecture is true if k < 2(s-1). When k = 0, this shows that any anisotropic form representing an element of the kernel of the natural restriction homomorphism W(F) -> W(F(p)) has dimension divisible by 2(s+1).
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页码:1437 / 1458
页数:22
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