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# Wydawnictwa / Czasopisma IMPAN / Fundamenta Mathematicae / Wszystkie zeszyty

## Embedding theorems for spaces of $\mathbb R$-places of rational function fields and their products

### Tom 218 / 2012

Fundamenta Mathematicae 218 (2012), 121-149 MSC: Primary 12J15; Secondary 12J25. DOI: 10.4064/fm218-2-2

#### Streszczenie

We study spaces $M(R(y))$ of $\mathbb R$-places of rational function fields $R(y)$ in one variable. For extensions $F|R$ of formally real fields, with $R$ real closed and satisfying a natural condition, we find embeddings of $M(R(y))$ in $M(F(y))$ and prove uniqueness results. Further, we study embeddings of products of spaces of the form $M(F(y))$ in spaces of $\mathbb R$-places of rational function fields in several variables. Our results uncover rather unexpected obstacles to a positive solution of the open question whether the torus can be realized as a space of $\mathbb R$-places.

#### Autorzy

• Katarzyna KuhlmannInstitute of Mathematics
Silesian University
40-007 Katowice, Poland
e-mail
• Franz-Viktor KuhlmannDepartment of Mathematics and Statistics