| 1. |
- Conder, Marsten, et al.
(author)
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Maximal Symmetry Groups of Hyperbolic three-manifolds
- 2006
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In: New Zealand Journal of Mathematics. - 1171-6096. ; 35:1, s. 37-62
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Journal article (peer-reviewed)abstract
- Every nite group acts as the full isometry group of some compact hyperbolic 3-manifold. In this paper we study those nite groups which act maximally, that is when the ratio jIsom+(M)j=vol(M)is maximal among all such manifolds. In two dimensions maximal symmetry groups are called Hurwitz groups, and arise as quotients of the (2,3,7){triangle group. Here we study quotients of the minimal co-volume lattice.
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| 2. |
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| 3. |
- Ivert, Anna-Karin, et al.
(author)
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Neighbourhood effects on immigrant children’s mental health and well being
- 2009
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In: Abstracts of the XXXIst International Congress on Law and Mental Health. ; , s. 207-208
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Conference paper (other academic/artistic)abstract
- The aim of this study was twofold; first we wanted to examine if there were actual differences in mental health problems between children with immigrant and Swedish background. Second, we wanted to examine the impact of neighborhood disadvantage, peer status, and family circumstances on mental health problems among children with immigrant background, as well as the association between ethnicity, level of neighborhood disadvantage, and contacts with Psychiatric Child and Youth Clinics. Multilevel analyses, using HLM 6.0, were carried out on data relating immigrant children’s mental health and contacts with psychiatric clinics to neighborhood characteristics. Results indicate that immigrant children tend to have more mental health problems than Swedish children, and factors related to the individual’s childhood family situation explain a considerable part of the differences. No significant differences in mental health problems were found between neighborhoods. The data used in the analysis are drawn from (1) the Swedish longitudinal database Project Metropolitan which consists of a cohort of approximately 15000 children born in 1953 and living in the Stockholm metropolitan area in 1963 and (2) The Stockholm Child-Psychiatric database containing approximately 20 000 children (including matched controls). Further research is needed on how social settings beyond the neighborhood can have an effect on children’s mental health, antisocial behavior, and well being.
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| 4. |
- Torstensson, Anna
(author)
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Projective linear groups as maximal symmetry groups
- 2008
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In: Glasgow Mathematical Journal. - 0017-0895. ; 50:1, s. 83-96
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Journal article (peer-reviewed)abstract
- A maximal symmetry group is a group of isomorphisms of a three-dimensional hyperbolic manifold of maximal order in relation to the volume of the manifold. In this paper we determine all maximal symmetry groups of the types PSL(2, q) and PGL(2, q). Depending on the prime p there are one or two such groups with q=pk and k always equals 1, 2 or 4.
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| 5. |
- Torstensson, Anna, et al.
(author)
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Using resultants for SAGBI basis verification in the univariate polynomial ring
- 2005
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In: Journal of Symbolic Computation. - : Elsevier BV. - 0747-7171. ; 40:3, s. 1087-1105
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Journal article (peer-reviewed)abstract
- A resultant-type identity for univariate polynomials is proved and used to characterise SAGBI bases of subalgebras generated by two polynomials. A new equivalent condition, expressed in terms of the degree of a field extension, for a pair of univariate polynomials to form a SAGBI basis is derived.
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