- Tytuł:
- Automatic search of automorphisms of Witt rings
- Autorzy:
-
Stępień, L.
Stępień, M. R. - Powiązania:
- https://bibliotekanauki.pl/articles/121845.pdf
- Data publikacji:
- 2011
- Wydawca:
- Uniwersytet Humanistyczno-Przyrodniczy im. Jana Długosza w Częstochowie. Wydawnictwo Uczelniane
- Tematy:
-
Witt rings
automorphisms
strong automorphisms
automorphisms of Witt rings
pierścień Witta
automorfizm
automorfizmy pierścieni Witta - Opis:
- The investigation of strong automorphisms of Witt rings is a difficult task because of variety of their structures. Cordes Theorem, known in literature as Harrison-Cordes criterion (cf. [1, Proposition 2.2], [3, Harrison's Criterion]), makes the task of describing all the strong automorphisms of a given (abstract) Witt ring W = (G, R) easier. By this theorem, it suffices to find all such automorphisms ơ of the group G that map the distiguished element -1 of the group G into itself (i.e. ơ(-1) = -1) in which the value sets of 1-fold Pfister forms are preserved in the following sense: ơ(D(1, α)) = D(1, ơ(α)) for all α ∈ G. We use the above criterion and the well-known structure of the group G as a vector space over two-element field F2 for searching all automorphisms of this group. Then we check Harrison-Cordes criterion for found automorpisms and obtain all the automorpisms of a Witt ring W. The task is easy for small rings (with small groups G). For searching of all strong automorpisms of bigger Witt rings we use a computer which automatizes the procedure described above. We present the algorithm for finding strong automorphisms of a Witt rings with finite group G and show how this algorithm can be optimized.
- Źródło:
-
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics; 2011, 16; 141-146
2450-9302 - Pojawia się w:
- Scientific Issues of Jan Długosz University in Częstochowa. Mathematics
- Dostawca treści:
- Biblioteka Nauki
Artykuł