A geometric connection between the split first and second rows of the Freudenthal-Tits magic square
- Author
- Anneleen De Schepper and Magali Victoor
- Organization
- Project
- Abstract
- A projective representation $G_1$ of a variety of the first row of the Freudenthal–Tits magic square can be obtained as the absolute geometry of a (symplectic) polarity $\rho$ of the projective representation $G_2$ of a variety one cell below. In this paper, we extend this geometric connection between $G_1$ and $G_2$ by showing that any nondegenerate quadric $Q$ of maximal Witt index containing $G_2$ gives rise to a variety isomorphic to $G_1$, in the sense that the symplecta of $G_2$ contained in totally isotropic subspaces of $Q$ are the absolute symplecta of a unique (symplectic) polarity $\rho$ of $G_2$. Except for the smallest case, we also show that any nondegenerate quadric containing $G_2$ has maximal Witt index; and in the largest case, we obtain that there are only three kinds of possibly degenerate quadrics containing the Cartan variety $\mathcal{E}_6(\mathbb{K})$.
- Keywords
- Veronese variety, Spherical buildings, Embeddings, Geometric hyperplanes
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Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-01H118M3X94CMSGPTX5Z4A20KV
- MLA
- De Schepper, Anneleen, and Magali Victoor. “A Geometric Connection between the Split First and Second Rows of the Freudenthal-Tits Magic Square.” INNOVATIONS IN INCIDENCE GEOMETRY - ALGEBRAIC, TOPOLOGICAL AND COMBINATORIAL, vol. 20, no. 1, 2023, pp. 1–53, doi:10.2140/iig.2023.20.1.
- APA
- De Schepper, A., & Victoor, M. (2023). A geometric connection between the split first and second rows of the Freudenthal-Tits magic square. INNOVATIONS IN INCIDENCE GEOMETRY - ALGEBRAIC, TOPOLOGICAL AND COMBINATORIAL, 20(1), 1–53. https://doi.org/10.2140/iig.2023.20.1
- Chicago author-date
- De Schepper, Anneleen, and Magali Victoor. 2023. “A Geometric Connection between the Split First and Second Rows of the Freudenthal-Tits Magic Square.” INNOVATIONS IN INCIDENCE GEOMETRY - ALGEBRAIC, TOPOLOGICAL AND COMBINATORIAL 20 (1): 1–53. https://doi.org/10.2140/iig.2023.20.1.
- Chicago author-date (all authors)
- De Schepper, Anneleen, and Magali Victoor. 2023. “A Geometric Connection between the Split First and Second Rows of the Freudenthal-Tits Magic Square.” INNOVATIONS IN INCIDENCE GEOMETRY - ALGEBRAIC, TOPOLOGICAL AND COMBINATORIAL 20 (1): 1–53. doi:10.2140/iig.2023.20.1.
- Vancouver
- 1.De Schepper A, Victoor M. A geometric connection between the split first and second rows of the Freudenthal-Tits magic square. INNOVATIONS IN INCIDENCE GEOMETRY - ALGEBRAIC, TOPOLOGICAL AND COMBINATORIAL. 2023;20(1):1–53.
- IEEE
- [1]A. De Schepper and M. Victoor, “A geometric connection between the split first and second rows of the Freudenthal-Tits magic square,” INNOVATIONS IN INCIDENCE GEOMETRY - ALGEBRAIC, TOPOLOGICAL AND COMBINATORIAL, vol. 20, no. 1, pp. 1–53, 2023.
@article{01H118M3X94CMSGPTX5Z4A20KV,
abstract = {{A projective representation $G_1$ of a variety of the first row of the Freudenthal–Tits magic square can be obtained as the absolute geometry of a (symplectic) polarity $\rho$ of the projective representation $G_2$ of a variety one cell below. In this paper, we extend this geometric connection between $G_1$ and $G_2$ by showing that any nondegenerate quadric $Q$ of maximal Witt index containing $G_2$ gives rise to a variety isomorphic to $G_1$, in the sense that the symplecta of $G_2$ contained in totally isotropic subspaces of $Q$ are the absolute symplecta of a unique (symplectic) polarity $\rho$ of $G_2$. Except for the smallest case, we also show that any nondegenerate quadric containing $G_2$ has maximal Witt index; and in the largest case, we obtain that there are only three kinds of possibly degenerate quadrics containing the Cartan variety $\mathcal{E}_6(\mathbb{K})$.}},
author = {{De Schepper, Anneleen and Victoor, Magali}},
issn = {{2640-7337}},
journal = {{INNOVATIONS IN INCIDENCE GEOMETRY - ALGEBRAIC, TOPOLOGICAL AND COMBINATORIAL}},
keywords = {{Veronese variety,Spherical buildings,Embeddings,Geometric hyperplanes}},
language = {{eng}},
number = {{1}},
pages = {{1--53}},
title = {{A geometric connection between the split first and second rows of the Freudenthal-Tits magic square}},
url = {{http://doi.org/10.2140/iig.2023.20.1}},
volume = {{20}},
year = {{2023}},
}
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