ISSN:
1573-0514
Keywords:
Witt ring
;
unramified étale cohomology
;
signature
;
real spectrum
;
cohomological dimension
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mathematics
Notes:
Abstract It is proved that for a smooth affine curveX over a local ring or global field, the graded Witt ring ofX is isomorphic to the graded unramified cohomology ring ofX. IfX is projective and has a rational point, the same result holds if and only if every quadratic space defined on the complement of a rational point extends toX. Such an extension is possible, for instance, if the canonical line bundle onX is a square in PicX.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00961333
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