Minkowski difference weight formulas
Abstract
Fix any complex Kac-Moody Lie algebra , and Cartan subalgebra . We study arbitrary highest weight -modules (with any highest weight , and let be the corresponding simple highest weight -module), and write their weight-sets . This is based on and generalizes the Minkowski decompositions for all and hulls , of Khare [J. Algebra. 2016 & Trans. Amer. Math. Soc. 2017] and Dhillon-Khare [Adv. Math. 2017 & J. Algebra. 2022]. Those works need a freeness property of the Dynkin graph nodes of integrability of : any sum of simple roots over are all weights of . We generalize it for all , by introducing nodes that record all the lost 1-dim. weights in . We show three applications (seemingly novel) for all of our -freeness: 1) Minkowski decompositions of all , subsuming those above for simples. 1) Characterization of these formulas. 1) For these, we solve the inverse problem of determining all with fixing weight-set of a Verma, parabolic Verma and . 2) At module level (by raising operators' actions), construction of weight vectors along -directions. 3) Lower bounds on the multiplicities of such weights, in all .
Cite
@article{arxiv.2409.12802,
title = {Minkowski difference weight formulas},
author = {G. Krishna Teja},
journal= {arXiv preprint arXiv:2409.12802},
year = {2024}
}
Comments
We isolate from our pre-print (ArXiv:2012.07775v2), weight-formula in Theorem A and conversely finding modules V with classical weights in Theorem B. All such weight-formulas are found in Theorem C, via freeness-nodes for weights (Definitions 1.8, 5.2). Thereby: "Jordan-Holder series'' factors of V with majority of weights explicitly, and some weight multiplicity bounds (Proposition 1.16)