Abstract
Let \({\cal C}\) be an extriangulated category and τ be any n-cluster tilting subcategory of \({\cal C}\). We consider the index with respect to τ and introduce the index Grothendieck group of τ. Using the index, we prove that the index Grothendieck group of τ is isomorphic to the Grothendieck group of \({\cal C}\), which implies that the index Grothendieck groups of any two n-cluster tilting subcategories are isomorphic. In particular, we show that the split Grothendieck groups of any two 2-cluster tilting subcategories are isomorphic. Then we develop a general framework for c-vectors of 2-Calabi-Yau extriangulated categories with respect to arbitrary 2-cluster tilting subcategories. We show that the c-vectors have the sign-coherence property and provide some formulas for calculating c-vectors.
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Acknowledgements
This work was supported by National Natural Science Foundation of China (Grant No. 12271257). The authors thank the reviewers for the careful reading, helpful comments and suggestions.
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Wang, L., Wei, J. & Zhang, H. Indices and c-vectors in extriangulated categories. Sci. China Math. 66, 1949–1964 (2023). https://doi.org/10.1007/s11425-022-2054-y
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DOI: https://doi.org/10.1007/s11425-022-2054-y