2026-03-13T07:40:02Z https://kanazawa-u.repo.nii.ac.jp/oai

oai:kanazawa-u.repo.nii.ac.jp:00000944 2024-05-09T02:51:16Z 11:12:16

Extremal lorentzian surfaces with null r-Planar geodesics in space forms Hasegawa, Kazuyuki Miura, Kouhei We show a congruence theorem for oriented Lorentzian surfaces with horizontal reflector lifts in pseudo-Riemannian space forms of neutral signature. As a corollary, a charactcrization theorem is obtained for the Lorentzian Boruvka spheres, that is, a full real analytic null r-planar geodesic immersion with vanishing mean curvature vector field is locally congruent to the Lorentzian Boruvka sphere in a 2r-dimensional space form of neutral signature. 出版者照会済 東北大学大学院理学研究科数学専攻 = Tohoku University, Mathematical Institute 2015-12-01 2017-10-02 eng journal article AM http://hdl.handle.net/2297/46778 https://kanazawa-u.repo.nii.ac.jp/records/944 https://doi.org/10.2748/tmj/1450798076 AA00863942 0040-8735 Tohoku Mathematical Journal 67 4 611 634 https://kanazawa-u.repo.nii.ac.jp/record/944/files/ED-PR-HASEGAWA-K-611.pdf application/pdf 198.6 kB 2017-10-02