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| Main Authors: | , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.01101 |
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| _version_ | 1866914173083975680 |
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| author | Belmans, Pieter Galkin, Sergey Leung, Naichung Conan Li, Changzheng Reineke, Markus Xiong, Rui |
| author_facet | Belmans, Pieter Galkin, Sergey Leung, Naichung Conan Li, Changzheng Reineke, Markus Xiong, Rui |
| contents | It is known that the semisimplicity of quantum cohomology implies the vanishing of off-diagonal Hodge numbers (Hodge--Tateness). We investigate which hyperplane sections of homogeneous varieties possess either of the two properties. We provide a new efficient criterion for non-semisimplicity of the small quantum cohomology ring of Fano manifolds that depends only on the Fano index and Betti numbers. We construct a bijection between Dynkin diagrams of types A, D or E, and complex Grassmannians with Hodge-Tate smooth hyperplane sections. By applying our criteria and using monodromy action, we completely characterize the semisimplicity of the small quantum cohomology of smooth hyperplane sections in the case of complex Grassmannians, and verify a conjecture of Benedetti and Perrin in the case of (co)adjoint Grassmannians. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_01101 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A-D-E diagrams, Hodge--Tate hyperplane sections and semisimple quantum cohomology Belmans, Pieter Galkin, Sergey Leung, Naichung Conan Li, Changzheng Reineke, Markus Xiong, Rui Algebraic Geometry It is known that the semisimplicity of quantum cohomology implies the vanishing of off-diagonal Hodge numbers (Hodge--Tateness). We investigate which hyperplane sections of homogeneous varieties possess either of the two properties. We provide a new efficient criterion for non-semisimplicity of the small quantum cohomology ring of Fano manifolds that depends only on the Fano index and Betti numbers. We construct a bijection between Dynkin diagrams of types A, D or E, and complex Grassmannians with Hodge-Tate smooth hyperplane sections. By applying our criteria and using monodromy action, we completely characterize the semisimplicity of the small quantum cohomology of smooth hyperplane sections in the case of complex Grassmannians, and verify a conjecture of Benedetti and Perrin in the case of (co)adjoint Grassmannians. |
| title | A-D-E diagrams, Hodge--Tate hyperplane sections and semisimple quantum cohomology |
| topic | Algebraic Geometry |
| url | https://arxiv.org/abs/2509.01101 |