arXiv subjects

Chih-Whi Chen

Publications and source records attributed to Chih-Whi Chen.

25 records · Page 2Linked to original sources

arXiv2018

Translated simple modules for Lie algebras and simple supermodules for Lie superalgebras

We prove that the tensor product of a simple and a finite dimensional $\mathfrak{sl}_n$-module has finite type socle. This is applied to reduce classification of simple $\mathfrak{q}(n)$-supermodules to that of simple $\mathfrak{sl}_n$-modules. Rough structure of simple $\mathfrak{q}(n)$-supermodules, considered as $\mathfrak{sl}_n$-modules, is described in terms of the combinatorics of category $\mathcal{O}$.

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arXiv2018

Extreme representations of semirings

This is a write-up of the discussions during the meetings of the study group on representation theory of semirings which was organized at the Department of Mathematics, Uppsala University, during the academic year 2017-2018. The main emphasis is on classification of various classes of "irreducible" representations for various concrete semirings.

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arXiv2018

The primitive spectrum and category O for the periplectic Lie superalgebra

We solve two problems in representation theory for the periplectic Lie superalgebra pe(n), namely the description of the primitive spectrum in terms of functorial realisations of the braid group and the decomposition of category O into indecomposable blocks. To solve the first problem we establish a new type of equivalence between category O for all (not just simple or basic) classical Lie superalgebras and a category of Harish-Chandra bimodules. The latter bimodules have a left action of the Lie superalgebra but a right action of the underlying Lie algebra. To solve the second problem we establish a BGG reciprocity result for the periplectic Lie superalgebra.

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arXiv2018

Simple supermodules over Lie superalgebras

We show that, for many Lie superalgebras admitting a compatible $\mathbb{Z}$-grading, Kac induction functor gives rise to a bijection between simple supermodules over a Lie superalgebra and simple supermodules over the even part of this Lie superalgebra. This reduces the classification problem for the former to the one for the latter. Our result applies to all classical Lie superalgebra of type $I$, in particular, to the general linear Lie superalgebra $\gl(m|n)$. In the latter case we also show that the rough structure of simple $\gl(m|n)$-supermodules and also that of Kac supermodules depends only on the annihilator of the $\mf{gl}(m)\oplus \mf{gl}(n)$-input and hence can be computed using the combinatorics of BGG category $\mathcal{O}$.

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arXiv2017

Affine Periplectic Brauer Algebras

We formulate Nazarov-Wenzl type algebras ${\widehat{P}_d^-}$ for the representation theory of the Periplectic Lie superalgebras $\mathfrak{p}(n)$. We establish a Arakawa-Suzuki type theorem to provide a connection between $\mathfrak{p}(n)$-representations and $\widehat{P}_d^-$-representations. We also consider various tensor product representations for $\widehat{P}_d^-$. The periplectic Brauer algebra $A_d$ defined by Moon is an quotient of $\widehat{P}_d^-$. In particular, actions induced by Jucys-Murphy elements can be obtained under the tensor product representation of $\widehat{P}_d^-$. Also, a Poincare-Birkhoff-Witt type basis for $\widehat{P}_d^-$ is obtained.

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arXiv2016

Reduction method for representations of queer Lie superalgebras

We develop a reduction procedure which provides an equivalence from an arbitrary block of the BGG category for the queer Lie superalgebra $\mathfrak{q}(n)$ to a "$\mathbb{Z}\pm s$-weights" ($s\in \mathbb{C}$) block of a BGG category for finite direct sum of queer Lie superalgebras. We give descriptions of blocks. We also establish equivalences between certain maximal parabolic subcategories for $\mathfrak{q}(n)$ and blocks of atypicality-one of the category of finite-dimensional modules for $\mathfrak{gl}(\ell|n-\ell)$.

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arXiv2016

Quantum group of type $A$ and representations of queer Lie superalgebra

We establish a maximal parabolic version of the Kazhdan-Lusztig conjecture \cite[Conjecture 5.10]{CKW} for the BGG category $\mathcal{O}_{k,ζ}$ of $\mathfrak{q}(n)$-modules of "$\pm ζ$-weights", where $k\leq n$ and $ζ\in\mathbb{C} \setminus \frac{1}{2} \mathbb{Z}$. As a consequence, the irreducible characters of these $\mathfrak{q}(n)$-modules in this maximal parabolic category are given by the Kazhdan-Lusztig polynomials of type $A$ Lie algebras. As an application, closed character formulas for a class of $\mathfrak{q}(n)$-modules resembling polynomial and Kostant modules of the general linear Lie superalgebras are obtained.

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