Blar i forfatter "Winther, Henrik"
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Almost complex homogeneous spaces with semi-simple isotropy
Winther, Henrik (Master thesis; Mastergradsoppgave, 2012-05)We classify the almost complex structures on homogeneous spaces M = G/H of real dimension less than or equal to 6 with semi-simple isotropy group H. -
Erratum to: Almost complex structures in 6D with nondegenerate Nijenhuis tensors and large symmetry groups
Kruglikov, Boris; Winther, Henrik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-23)We correct an error in the second part of Theorem 3 of our original paper. -
Lie-Algebraic Approaches to Highly Symmetric Geometries
Winther, Henrik (Doctoral thesis; Doktorgradsavhandling, 2017-02-24)We facilitate the exploration and development of geometry by symmetry-based methods. To this end, we answer several natural questions that appear when considering symmetries, for particular examples of geometries -
Non-degenerate para-complex structures in 6D with large symmetry groups
Kruglikov, Boris; Winther, Henrik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-20)For an almost product structure J on a manifold M of dimension 6 with non-degenerate Nijenhuis tensor N J, we show that the automorphism group G=Aut(M,J) has dimension at most 14. In the case of equality G is the exceptional Lie group G∗2. The next possible symmetry dimension is proved to be equal to 10, and G has Lie algebra sp(4,R). Both maximal and submaximal symmetric structures are globally ... -
Submaximally symmetric almost quaternionic structures
Kruglikov, Boris; Winther, Henrik; Zalabová, Lenka (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-10)The symmetry dimension of a geometric structure is the dimension of its symmetry algebra. We investigate symmetries of almost quaternionic structures of quaternionic dimension <i>n</i>. The maximal possible symmetry is realized by the quaternionic projective space H<i>P<sup> n</sup></i>, which is flat and has the symmetry algebra sl(<i>n</i> + 1, H) of dimension 4<i>n</i><sup> 2</sup> + ...