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Algebra and Discrete Mathematics, 2003, Issue 3, Pages 1–6
(Mi adm381)
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RESEARCH ARTICLE
$N$ – real fields
Shalom Feigelstock Department of Mathematics, Bar–Ilan University, Ramat Gan,
Israel
Abstract:
A field $F$ is $n$-real if $-1$ is not the sum of $n$ squares in $F$. It is shown that a field $F$ is $m$-real if and only if $\text{rank }(AA^t)=\text{rank }(A)$ for every $n\times m$ matrix $A$ with entries from $F$. An $n$-real field $F$ is $n$-real closed if every proper algebraic extension of $F$ is not $n$-real. It is shown that if a $3$-real field $F$ is $2$-real closed, then $F$ is a real closed field. For $F$ a quadratic extension of the field of rational numbers, the greatest integer $n$ such that $F$ is $n$-real is determined.
Keywords:
$n$-real, $n$-real closed.
Received: 03.03.2003 Revised: 23.10.2003
Citation:
Shalom Feigelstock, “$N$ – real fields”, Algebra Discrete Math., 2003, no. 3, 1–6
Linking options:
https://www.mathnet.ru/eng/adm381 https://www.mathnet.ru/eng/adm/y2003/i3/p1
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Abstract page: | 136 | Full-text PDF : | 44 | First page: | 1 |
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