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Haibao Duan

Publications and source records attributed to Haibao Duan.

36 records · Page 2Linked to original sources
arXiv2013

The fixed set of the inverse involution on a Lie group

In [H. Duan and S. Liu, The isomorphism type of the centralizer of an element in a Lie group, Journal of algebra, 376(2013), 25-45], we have determined the isomorphism type of the centralizer of an element in a simpe Lie group. As a sequel to [H. Duan and S. Liu, The isomorphism type of the centralizer of an element in a Lie group, Journal of algebra, 376(2013), 25-45.] we present a general procedure to calculate the isomorphism type of the fixed set of the inverse involution on a Lie group.

math.GR↗
arXiv2013

A K-theory approach to the tangent invariants of blow-ups

We extend the formula for the Chern classes of blow-ups of algebraic varieties due to Porteous and Lascu-Scott, and of symplectic and complex manifolds due to Geiges and Pasquotto, to the blow-ups of almost complex manifolds. Our approach is based on a concrete partition for the tangent bundle of a blow-up. The use of topological K-theory of vector bundles simplifies the classical approaches.

math.AT↗
arXiv2012

The isomorphism type of the centralizer of an element in a Lie group

Let G be an 1-connected simple Lie group, and let x\inG be a group element. We determine the isomorphism type of the centralizer C_{x} in term of a minimal geodesic joinning the group unit e\inG to x. This result is applied to classify the isomorphism types of maximal subgroups of maximal rank of G, and the isomorphism types of parabolic subgroups of G.

math.GR↗
arXiv2010

The near-Hopf ring structure on the integral cohomology of 1-connected Lie groups

Let G be an exceptional Lie group with a maximal torus T. Based on Schubert calculus on the flag manifold G/T we have described the integral cohomology ring H*(G) by explicitely constructed generators in [DZ2], and determined the structure of H*(G;F_{p}) as a Hopf algebra over the Steenrod algebra in[DZ3]. In this sequel to [DZ2], [DZ3] we obtain the near--Hopf ring structure on H*(G).

math.AT↗
arXiv2010

Schubert calculus and the Hopf algebra structures of exceptional Lie groups

Let G be an exceptional Lie group with a maximal torus T. Based on common properties in the Schubert presentation of the cohomology ring H*(G/T;F_{p}) DZ1, and concrete expressions of generalized Weyl invariants for G over F_{p}, we obtain a unified approach to the structure of H*(G;F_{p}) as a Hopf algebra over the Steenrod algebra A_{p}. The results has been applied in Du2 to determine the near--Hopf ring structure on the integral cohomology of all exceptional Lie groups.

math.AT↗
arXiv2008

Homology rigidity of Grassmannians

Applying the theory of Gröbner basis to the Schubert presentation of the cohomology of Grassmannians, we extend the homology rigidity results known for the classical Grassmannians to the exceptional cases.

math.AT↗
arXiv2008

The Chow rings of generalized Grassmannians

Based on the Basis theorem of Bruhat--Chevalley [C] and the formula for multiplying Schubert classes obtained in [D\QTR{group}{u}] and programed in [DZ$_{\QTR{group}{1}}$], we introduce a new method computing the Chow rings of flag varieties (resp. the integral cohomology of homogeneous spaces). The method and results of this paper have been extended in [DZ$_{3}$, DZ$_{4}$] to obtain the integral cohomology rings of all complete flag manifolds, and to construct the integral cohomologies of Lie groups in terms of Schubert classes.

math.AG↗
arXiv2005

Algorithm for multiplying Schubert classes

Based on the multiplicative rule of Schubert classes obtained in [Du3], we present an algorithm computing the product of two arbitrary Schubert classes. As a result, the algorithm gives also a method to compute the integral cohomology ring of a flag manifold independent of the classical spectral sequence technique due to Leray and Borel.

math.AG↗
arXiv2005

A homotopy aspect of representation theory

We bring a linkage from representation theory of Lie groups to homotopy theory for maps between flag manifolds. As applications we derive from representation theory abundant families of homotopy classes of maps between flag manifolds whose induced cohomology homomorphisms can be read from the characters of the representations.

math.AT↗
arXiv2005

Circle bundles over 4-manifolds

Every 1-connected topological 4-manifold M admits a $S^{1}$-covering by $#_{r-1}S^{2}\times S^{3}$, where $r=$rank$H^{2}(M;\QTR{Bbb}{Z})$.

math.GT↗
arXiv2005

A unified formula for Steenrod operations in flag manifolds

The classical Schubert cells on a flag manifold G/H give a cell decomposition for G/H whose Kronecker duals (known as Schubert classes) form an additive base for the integral cohomology H^{\ast}(G/H). We present a formula that expresses Steenrod mod-p operations on Schubert classes in G/H in terms of Cartan numbers of G.

math.AT↗
arXiv2004

Morse functions and cohomology of homogeneous spaces

This article arose from a series of three lectures given at the Banach Center, Warsaw, during period of 24 March to 13 April, 2003. Morse functions are useful tool in revealing the geometric formation of its domain manifolds $M$. They define the handle decompositions of $M$ from which the additive homologies $H_{\ast}(M)$ may be constructed. In these lectures two further questions were emphasized. (1) How to find a Morse function on a given manifold? (2) From Morse functions can one derive the multiplicative cohomology rather than the additive homology?

math.AT↗
arXiv2004

Non-zero degree maps between $2n$-manifolds

Thom-Pontrjagin constructions are used to give a computable necessary and sufficient condition when a homomorphism $ϕ: H^n(L;Z)\to H^n(M;Z)$ can be realized by a map $f:M\to L$ of degree $k$ for closed $(n-1)$-connected $2n$-manifolds $M$ and $L$, $n>1$. A corollary is that each $(n-1)$-connected $2n$-manifold admits selfmaps of degree larger than 1, $n>1$. In the most interesting case of dimension 4, with the additional surgery arguments we give a necessary and sufficient condition for the existence of a degree $k$ map from a closed orientable 4-manifold $M$ to a closed simply connected 4-manifold $L$ in terms of their intersection forms, in particular there is a map $f:M\to L$ of degree 1 if and only if the intersection form of $L$ is isomorphic to a direct summand of that of $M$.

math.GT↗
arXiv2003

A Problem of Hsiang-Palais-Terng on isoparametric submanifolds

We solve the problem raised by Hsiang, Palais and Terng in [The topology of isoparametric submanifolds, JDG, 27(1988), 423-460]: Is it possible to have an isoparametric foliation on R^{52} whose marked Dynkin giagram is of type D_4 and with all multiplicities uniformly equal to 4?

math.DG↗
arXiv2003

Multiplicative rule of Schubert classes

Let G be a compact connected Lie group and H, the centralizer of a one-parameter subgroup in G. Combining the ideas of Bott-Samelson resulotions of Schubert varieties and the enumerative formula on a twisted products of 2-spheres obatained in {Du2], we obtain a closed formula for multiplying Schubert classes in the flag manifold G/H.

math.AG↗
arXiv2003

On the inverse Kostka matrix

We present both a combinatorial characterization and a recurrent formula for the entries of the inverse Kostka matrix. An application to the topology of the classifying space BU(n) is obtained.

math.CO↗