On the substitution theorem for rings of semialgebraic functions
Let R⊂F be an extension of real closed fields and S(M,R) the ring of (continuous) semialgebraic functions on a semialgebraic set M⊂Rn. We prove that every R-homomorphism φ:S(M,R)→F is essentially the evaluation homomorphism at a certain point p∈Fn \em adjacent \em to the extended semialgebraic set M...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/33872 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/33872 |
| Access Level: | acceso abierto |
| Palabra clave: | 512 semialgebraic set ring of semialgebraic functions extension of coefficients evaluation homomorphisms substitution theorem weak continuous extension property Matemáticas (Matemáticas) Álgebra 12 Matemáticas 1201 Álgebra |
| Sumario: | Let R⊂F be an extension of real closed fields and S(M,R) the ring of (continuous) semialgebraic functions on a semialgebraic set M⊂Rn. We prove that every R-homomorphism φ:S(M,R)→F is essentially the evaluation homomorphism at a certain point p∈Fn \em adjacent \em to the extended semialgebraic set MF. This type of result is commonly known in Real Algebra as Substitution Theorem. In case M is locally closed, the results are neat while the non locally closed case requires a more subtle approach and some constructions (weak continuous extension theorem, \em appropriate immersion \em of semialgebraic sets) that have interest on their own. We afford the same problem for the ring of bounded (continuous) semialgebraic functions getting results of a different nature. |
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