Abstract
We define the formal affine Demazure algebra and a formal affine Hecke algebra associated to a Kac-Moody root system. We prove structure theorems for these algebras, and use them to extend several results and constructions (presentation in terms of generators and relations, coproduct and product structures, filtration by codimension of Bott-Samelson classes, root polynomials and multiplication formulas) that were previously known for finite root systems.
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Acknowledgments
B. C. was supported by the French Agence Nationale de la Recherche (ANR) under reference ANR-12-BL01-0005. K. Z. was partially supported by the NSERC Discovery Grant RGPIN-2015-04469. C. Z. was supported by PIMS and NSERC grants of S. Gille and V. Chernousov in 2014, and would like to thank S. Kumar, T. Zhang and G. Zhao for helpful discussions, and to the Max Planck Institute for Mathematics for hospitality during the visit in May, 2014.
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Calmès, B., Zainoulline, K. & Zhong, C. Formal Affine Demazure and Hecke Algebras of Kac-Moody Root Systems. Algebr Represent Theor 23, 1031–1050 (2020). https://doi.org/10.1007/s10468-019-09880-w
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DOI: https://doi.org/10.1007/s10468-019-09880-w