Gruber, Jonathan2022-03-282022-03-282022-03-282022-03-0210.1090/ert/599https://infoscience.epfl.ch/handle/20.500.14299/186602WOS:000768835100001Let G be a simple algebraic group over an algebraically closed field F of characteristic p >= h, the Coxeter number of G. We observe an easy 'recursion formula' for computing the Jantzen sum formula of a Weyl module with p-regular highest weight. We also discuss a 'duality formula' that relates the Jantzen sum formula to Andersen's sum formula for tilting filtrations and we give two different representation theoretic explanations of the recursion formula. As a corollary, we also obtain an upper bound on the length of the Jantzen filtration of a Weyl module with p-regular highest weight in terms of the length of the Jantzen filtration of a Weyl module with highest weight in an adjacent alcove.Mathematicskazhdan-lusztig conjectureaffine lie-algebrasfiltrationstext::journal::journal article::research article