2024-03-28T17:02:38Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/698622022-11-17T02:08:08Zhdl_2115_45007hdl_2115_116D_n-geometry and singularities of tangent surfacesIshikawa, GooMachida, YoshinoriTakahashi, Masatomoopen access410The geometric model for Dn-Dynkin diagram is explicitly constructed and associated generic singularities of tangent surfaces are classified up to local diffeomorphisms. We observe, as well as the triality in D4 case, the difference of the classification for D3,D4,D5 and Dn(n ≥ 6), and a kind of stability of the classification in Dn for n → ∞. Also we present the classifications of singularities of tangent surfaces for the cases B3,A3 = D3,G2,C2 = B2 and A2 arising from D4 by the processes of foldings and removings.Department of Mathematics, Hokkaido University2014-07-07engdepartmental bulletin paperVoRhttps://doi.org/10.14943/84202http://hdl.handle.net/2115/6986210.14943/84202Hokkaido University Preprint Series in Mathematics1058220https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/69862/1/pre1058.pdfapplication/pdf219.08 KB2014-07-07