A Hermitian Analogue of the Bröcker–prestel Theorem
نویسنده
چکیده
The Bröcker–Prestel local-global principle characterizesweak isotropy of quadratic forms over a formally real field in terms of weak isotropy over the henselizations and isotropy over the real closures of that field. A hermitian analogue of this principle is presented for algebras of index at most two. An improved result is also presented for algebras with a decomposable involution, algebras of pythagorean index atmost two, and algebras over SAP and ED fields.
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