Descent Monomials, P-Partitions and Dense Garsia-Haiman Modules

A two-variable analogue of the descents monomials is defined and is shown to form a basis for the dense Garsia-Haiman modules. A two-variable generalization of a decomposition of a P-partition is shown to give the algorithm for the expansion into this descent basis. Some examples of dense Garsia-Haiman modules include the coinvariant rings associated with certain complex reflection groups.     

On the normality of the rings of Schubert varieties

We prove that the cone over a Schubert variety inG/P (P being a maximal parabolic subgroup of classical type) is normal by exhibiting a 2-regular sequence inR(w) (the homogeneous coordinate ring of the Schubert varietyX(w) inG/P under the canonical protective embeddingG/P ⊂→ (p (H° G/P,L)),L being the ample generator of (PicG/P), which vanishes on the singular locus ofX(w). We also prove the surjectivity ofH° (G/Q, L) H° (X(w), L), whereQ is a classical parabolic subgroup (not necessarily maximal) ofG andL is an ample line bundle onG/Q.     

Monomial Realization of the Crystals Over U q (A ∞) and the Quantum Monster Algebra

We give new realizations of the crystal bases of the Verma modules and the irreducible highest weight modules over the quantum generalized Kac–Moody algebra U _q (A _∞) and the quantum Monster algebra using Nakajima monomials. Moreover, another realization of the crystals B(∞) and B(λ) over U _q (A _∞) using triangular matrices and tableaux are given.     

A_4型量子群中紧单项式的区域

整体晶体基(又称为典范基)在量子群及其表示理论中起着重要的作用. 紧单项式是典范基中最简单的元素.本文基于Lusztig的工作来确定A_4型量子群中紧单项式的区域.     

Quadratic nonsymmetric quaternary operads

We use computational linear algebra and commutative algebra to study spaces of relations satisfied by quadrilinear operations. The relations are analogues of associativity in the sense that they are quadratic (every term involves two operations) and nonsymmetric (every term involves the identity permutation of the arguments). We focus on determining those quadratic relations whose cubic consequences have minimal or maximal rank. We approach these problems from the point of view of the theory of algebraic operads.     

Minimal systems of binomial generators and the indispensable complex of a toric ideal

Let be a vector configuration and its corresponding toric ideal. The paper consists of two parts. In the first part we completely determine the number of different minimal systems of binomial generators of . In the second part we associate to a simplicial complex . We show that the vertices of correspond to the indispensable monomials of the toric ideal , while one dimensional facets of with minimal binomial -degree correspond to the indispensable binomials of .

     

Tight Monomials for Type G 2 and A 3

The global crystal basis or canonical basis plays an important role in the theory of the quantum groups and their representations. The tight monomials are the simplest elements in the canonical basis. Based on Reineke, Deng, and Du's work, the tight monomials in quantized enveloping algebra of type G₂ and A₃ are completely determined in this article.     

Desingularizations of quiver Grassmannians via graded quiver varieties

Inspired by recent work of Cerulli, Feigin and Reineke on desingularizations of quiver Grassmannians of representations of Dynkin quivers, we obtain desingularizations in considerably more general situations and in particular for Grassmannians of modules over iterated tilted algebras of Dynkin type. Our desingularization map is constructed from Nakajima's desingularization map for graded quiver varieties.     

An operator-theoretical treatment of the Maskawa–Nakajima equation in the massless abelian gluon model

The Maskawa–Nakajima equation has attracted considerable interest in elementary particle physics. From the viewpoint of operator theory, we study the Maskawa–Nakajima equation in the massless abelian gluon model. We first show that there is a nonzero solution to the Maskawa–Nakajima equation when the parameter λ   satisfies λ>2$\lambda >2$. Moreover, we show that the solution is infinitely differentiable and strictly decreasing. We thus conclude that the massless abelian gluon model generates the nonzero quark mass spontaneously and exhibits the spontaneous chiral symmetry breaking when λ>2$\lambda >2$. We next show that there is a unique solution 0 to the Maskawa–Nakajima equation when 0<λ<1$0<\lambda <1$, from which we conclude that each quark remains massless and that the model realizes the chiral symmetry when 0<λ<1$0<\lambda <1$.