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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2014 Volume 423, Pages 264–275 (Mi znsl6007)

This article is cited in 2 papers

Homomorphisms and involutions of unramified henselian division algebras

S. V. Tikhonova, V. I. Yanchevskiib

a Belarusian State University, Minsk, Belarus
b Institute of Mathematics of the National Academy of Sciences of Belarus, Minsk, Belarus

Abstract: Let $K$ be a henselian field with the residue field $\overline K$, and let $\mathcal A_1$, $\mathcal A_2$ be finite dimensional division unramified $K$-algebras with residue algebras $\overline{\mathcal A}_1$ and $\overline{\mathcal A}_2$. Further, let $\mathrm{Hom}_K(\mathcal A_1,\mathcal A_2)$ be the set of nonzero $K$-homomorphisms from $\mathcal A_1$ to $\mathcal A_2$. We prove that there is a natural bijection between the set of nonzero $\overline K$-homomorphisms from $\overline{\mathcal A}_1$ to $\overline{\mathcal A}_2$ and the factor set of $\mathrm{Hom}_K(\mathcal A_1,\mathcal A_2)$ under the equivalence relation: $\phi_1\sim\phi_2$ $\Leftrightarrow$ there exists $m\in1+M_{\mathcal A_2}$ such that $\phi_2=\phi_1i_m$, where $i_m$ is the inner automorphism of $\mathcal A_2$ induced by $m$.
A similar result is obtained for unramified algebras with involutions.

Key words and phrases: unramified division algebra, henselian division algebra, involution.

UDC: 512.7

Received: 31.01.2014


 English version:
Journal of Mathematical Sciences (New York), 2015, 209:4, 657–664

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