arXiv subjects
Publications and source records attributed to Noriyuki Abe.
We study Braden-MacPherson sheaves on the moment graph associated to the set of of alcoves. We define an action of Soergel bimodules on the category of Braden-MacPherson sheaves. We also prove a certain stability of morphisms between Braden-MacPherson sheaves.
We study the first extension groups between Verma modules. There was a conjecture which claims that the dimensions of the higher extension groups between Verma modules are the coefficients of $R$-polynomials defined by Kazhdan-Lusztig. This conjecture was known as the Gabber-Joseph conjecture (although Gebber and Joseph did not state.) However, Boe gives a counterexample to this conjecture. In this paper, we study how far are the dimensions of extension groups from the coefficients of $R$-polynomials.
Williamson defined the category of singular Soergel bimodules attached to a reflection faithful representation of a Coxeter group. We generalize this construction to more general realizations of Coxeter groups.
We establish a theory of singular Soergel bimodules which is a generalization of (a part of) Williamson's theory. We use a formulation of Soergel bimodules developed by the author.
Suppose that $G$ is the group of $F$-points of a connected reductive group over $F$, where $F/\mathbb{Q}_p$ is a finite extension. We study the (topological) irreducibility of principal series of $G$ on $p$-adic Banach spaces. For unitary inducing representations we obtain an optimal irreducibility criterion, and for $G = \mathrm{GL}_n(F)$ (as well as for arbitrary split groups under slightly stronger conditions) we obtain a variant of Schneider's conjecture [Sch06, Conjecture 2.5]. In general we reduce the irreducibility problem to smooth inducing representations and almost simple simply-connected $G$. Our methods include locally analytic representation theory, the bifunctor of Orlik--Strauch, translation functors, as well as new results on reducibility points of smooth parabolic inductions.
We establish an optimal (topological) irreducibility criterion for $p$-adic Banach principal series of $\mathrm{GL}_{n}(F)$, where $F/\mathbb{Q}_p$ is finite and $n \le 3$. This is new for $n = 3$ as well as for $n = 2$, $F \ne \mathbb{Q}_p$ and establishes a refined version of Schneider's conjecture [Sch06, Conjecture 2.5] for these groups.
Let $G$ be any connected reductive $p$-adic group. Let $K\subset G$ be any special parahoric subgroup and $V,V'$ be any two irreducible smooth $\overline {\mathbb F}_p[K]$-modules. The main goal of this article is to compute the image of the Hecke bi-module $\operatorname{End}_{\overline {\mathbb F}_p[K]}(\operatorname{c-Ind}_K^G V, \operatorname{c-Ind}_K^G V')$ by the generalized Satake transform and to give an explicit formula for its inverse, using the pro-$p$ Iwahori Hecke algebra of $G$. This immediately implies the "change of weight theorem" in the proof of the classification of mod $p$ irreducible admissible representations of $G$ in terms of supersingular ones. A simpler proof of the change of weight theorem, not using the pro-$p$ Iwahori Hecke algebra or the Lusztig-Kato formula, is given when $G$ is split (and in the appendix when $G$ is quasi-split, for almost all $K$).
We give an action of the Hecke category on the principal block $\mathrm{Rep}_0(G_1T)$ of $G_1T$-modules where $G$ is a connected reductive group over an algebraically closed field of characteristic $p > 0$, $T$ a maximal torus of $G$ and $G_1$ the Frobenius kernel of $G$. To define it, we define a new category with a Hecke action which is equivalent to the combinatorial category defined by Andersen-Jantzen-Soergel.
In the previous paper, we defined a new category which categorifies the Hecke algebra. This is a generalization of the theory of Soergel bimodules. To prove theorems, the existences of certain homomorphisms between Bott-Samelson bimodules are assumed. In this paper, we prove this assumption. We only assume the vanishing of certain two-colored quantum binomial coefficients.
For a Coxeter system and a representation $V$ of this Coxeter system, Soergel defined a category which is now called the category of Soergel bimodules and proved that this gives a categorification of the Hecke algebra when $V$ is reflection faithful. Elias and Williamson defined another category even when $V$ is not reflection faithful and they proved that this category is equivalent to the category of Soergel bimodules when $V$ is reflection faithful. Moreover they proved the categorification theorem for their category with less assumptions on $V$. In this paper, we give a "bimodule theoretic" definition of the category of Elias-Williamson and reprove the categorification theorem.
We give an equivalence of categories between certain subcategories of modules of pro-$p$-Iwahori Hecke algebras and modulo $p$ representations.
We calculate the extension groups between simple modules of pro-$p$-Iwahori Hecke algebras.
The pro-$p$-Iwahori Hecke algebra has an involution $ι$ defined in terms of Iwahori-Matsumoto basis. Then for a module $π$ of pro-$p$-Iwahori Hecke, $π^ι= π\circ ι$ is also a module. We calculate $π^ι$ for simple modules $π$. We also calculate the dual of $π$.
Let $F$ be a local field with residue characteristic $p$, let $C$ be an algebraically closed field of characteristic $p$, and let $\mathbf{G}$ be a connected reductive $F$-group. In a previous paper, Florian Herzig and the authors classified irreducible admissible $C$-representations of $G=\mathbf{G}(F)$ in terms of supercuspidal representations of Levi subgroups of $G$. Here, for a parabolic subgroup $P$ of $G$ with Levi subgroup $M$ and an irreducible admissible $C$-representation $τ$ of $M$, we determine the lattice of subrepresentations of $\mathrm{Ind}_P^G τ$ and we show that $\mathrm{Ind}_P^G χτ$ is irreducible for a general unramified character $χ$ of $M$. In the reverse direction, we compute the image by the two adjoints of $\mathrm{Ind}_P^G$ of an irreducible admissible representation $π$ of $G$. On the way, we prove that the right adjoint of $\mathrm{Ind}_P^G $ respects admissibility, hence coincides with Emerton's ordinary part functor $\mathrm{Ord}_{\overline{P}}^G$ on admissible representations.
Let $F$ be locally compact field with residue characteristic $p$, and $\mathbf{G}$ a connected reductive $F$-group. Let $\mathcal{U}$ be a pro-$p$ Iwahori subgroup of $G = \mathbf{G}(F)$. Fix a commutative ring $R$. If $π$ is a smooth $R[G]$-representation, the space of invariants $π^{\mathcal{U}}$ is a right module over the Hecke algebra $\mathcal{H}$ of $\mathcal{U}$ in $G$. Let $P$ be a parabolic subgroup of $G$ with a Levi decomposition $P = MN$ adapted to $\mathcal{U}$. We complement previous investigation of Ollivier-Vignéras on the relation between taking $\mathcal{U}$-invariants and various functor like $\mathrm{Ind}_P^G$ and right and left adjoints. More precisely the authors' previous work with Herzig introduce representations $I_G(P,σ,Q)$ where $σ$ is a smooth representation of $M$ extending, trivially on $N$, to a larger parabolic subgroup $P(σ)$, and $Q$ is a parabolic subgroup between $P$ and $P(σ)$. Here we relate $I_G(P,σ,Q)^{\mathcal{U}}$ to an analogously defined $\mathcal{H}$-module $I_\mathcal{H}(P,σ^{\mathcal{U}_M},Q)$, where $\mathcal{U}_M = \mathcal{U}\cap M$ and $σ^{\mathcal{U}_M}$ is seen as a module over the Hecke algebra $\mathcal{H}_M$ of $\mathcal{U}_M$ in $M$. In the reverse direction, if $\mathcal{V}$ is a right $\mathcal{H}_M$-module, we relate $I_\mathcal{H}(P,\mathcal{V},Q)\otimes \textrm{c-Ind}_\mathcal{U}^G\mathbf{1}$ to $I_G(P,\mathcal{V}\otimes_{\mathcal{H}_M}\textrm{c-Ind}_{\mathcal{U}_M}^M\mathbb{1},Q)$. As an application we prove that if $R$ is an algebraically closed field of characteristic $p$, and $π$ is an irreducible admissible representation of $G$, then the contragredient of $π$ is $0$ unless $π$ has finite dimension.
This is a list of questions raised by our joint work arXiv:1412.0737 and its sequels.
We give some properties of parabolic inductions and their adjoint functors for pro-$p$-Iwahori Hecke algebras.
Let F be a locally compact non-archimedean field, p its residue characteristic, and G a connected reductive group over F. Let C an algebraically closed field of characteristic p. We give a complete classification of irreducible admissible C-representations of G = G(F), in terms of supercuspidal C-representations of the Levi subgroups of G, and parabolic induction. Thus we push to their natural conclusion the ideas of the third-named author, who treated the case G = GL_m, as further expanded by the first-named author, who treated split groups G. As in the split case, we first get a classification in terms of supersingular representations of Levi subgroups, and as a consequence show that supersingularity is the same as supercuspidality.