De Rham Cohomology and Hodge Decomposition For Quantum Groups

Let be one of the N²-dimensionalbicovariant first order differential calculi for the quantumgroups GL_q(N), SL_q(N), SO_q(N), or Sp_q(N), where q is a transcendentalcomplex number and z is a regular parameter. It is shown thatthe de Rham cohomology of Woronowicz' external algebra coincides with the de Rham cohomologiesof its left-coinvariant, its right-coinvariant and its (two-sided)coinvariant subcomplexes. In the cases GL_q(N) and SL_q(N) thecohomology ring is isomorphic to the coinvariant external algebra and to the vector space of harmonic forms. We prove a Hodge decomposition theorem in thesecases. The main technical tool is the spectral decompositionof the quantum Laplace-Beltrami operator. 2000 MathematicalSubject Classification: 46L87, 58A12, 81R50.     

Infinitesimal Stokes’ Formula for Higher-Order de Rham Complexes

A higher-order de Rham complex dR [14] is associated with a commutative algebra A and a sequence of positive integers = (₁₂... It is called regular if is nondecreasing. We extend the algebraic definitions of the Lie derivative and interior product with respect to a derivation of A, to higher-order differential forms. These allow us to prove a generalization of the infinitesimal Stokes formula (also known as the Cartan homotopy formula) for higher regular de Rham complexes. In particular, this implies the homotopy invariance property of higher regular de Rham cohomologies for differentiable manifolds.     

Noncommutative differential geometry on the quantum SU(2), I: An algebraic viewpoint

We compute the cyclic homology of the coordinate ring A(SL_q(2)) of the quantum algebraic group SL _q (2). We observe a degeneration of the noncommutative de Rham complex. The results are also verified from the point of view of Connes' noncommutative differential geometry.     

Spectrum of a class of fourth order left-definite differential operators

The spectrum of a class of fourth order left-definite differential operators is studied. By using the theory of indefinite differential operators in Krein space and the relationship between left-definite and right-definite operators, the following conclusions are obtained： if a fourth order differential operator with a self-adjoint boundary condition that is left-definite and right-indefinite, then all its eigenvalues are real, and there exist countably infinitely many positive and negative eigenvalues which are unbounded from below and above, have no finite cluster point and can be indexed to satisfy the inequality …≤λ-2≤λ-1≤λ-0〈0〈λ0≤λ1≤λ2≤…     

Isogeny Covariant Differential Modular Forms and the Space of Elliptic Curves up to Isogeny

The purpose of this article is to develop the theory of differential modular forms introduced by A. Buium. The main points are the construction of many isogeny covariant differential modular forms and some auxiliary (nonisogeny covariant) forms and an extension of the classical theory of Serre differential operators on modular forms to a theory of -Serre differential operators on differential modular forms. As an application, we shall give a geometric realization of the space of elliptic curves up to isogeny.     

On Compact Solvability of Differentials of an Elliptic Differential Complex

We find sufficient conditions for compact solvability of differentials of an elliptic differential complex on a noncompact Riemannian manifold. As the main example we consider the de Rham complex of differential forms on a manifold with cylindrical ends.     

Graded Jacobi operators on the algebra of differential forms

One-to-one correspondences are established between the set ofall nondegenerate graded Jacobi operators of degree -1 defined onthe graded algebra of differential forms on a smooth, oriented,Riemannian manifold M, the space of bundle isomorphisms , and the space of nondegenerate derivations of degree 1 havingnull square. Derivations with this property, andJacobi structures of odd -degree are also studied throughthe action of the automorphism group of .     

A cohomology for vector valued differential forms

A rather simple natural outer derivation of the graded Lie algebra of all vector valued differential forms with the Frölicher-Nijenhuis bracket turns out to be a differential and gives rise to a cohomology of the manifold, which is functorial under local diffeomorphisms. This cohomology is determined as the direct product of the de Rham cohomology space and the graded Lie algebra of traceless vector valued differential forms, equipped with a new natural differential concomitant as graded Lie bracket. We find two graded Lie algebra structures on the space of differential forms. Some consequences and related results are also discussed.     

Abstract Differential Geometry, Differential Algebras of Generalized Functions, and de Rham Cohomology

Abstract differential geometry is a recent extension of classical differential geometry on smooth manifolds which, however, does no longer use any notion of Calculus. Instead of smooth functions, one starts with a sheaf of algebras, i.e., the structure sheaf, considered on an arbitrary topological space, which is the base space of all the sheaves subsequently involved. Further, one deals with a sequence of sheaves of modules, interrelated with appropriate differentials, i.e., suitable Leibniz sheaf morphisms, which will constitute the differential complex. This abstract approach captures much of the essence of classical differential geometry, since it places a powerful apparatus at our disposal which can reproduce and, therefore, extend fundamental classical results. The aim of this paper is to give an indication of the extent to which this apparatus can go beyond the classical framework by including the largest class of singularities dealt with so far. Thus, it is shown that, instead of the classical structure sheaf of algebras of smooth functions, one can start with a significantly larger, and nonsmooth, sheaf of so-called nowhere dense differential algebras of generalized functions. These latter algebras, which contain the Schwartz distributions, also provide global solutions for arbitrary analytic nonlinear PDEs. Moreover, unlike the distributions, and as a matter of physical interest, these algebras can deal with the vastly larger class of singularities which are concentrated on arbitrary closed, nowhere dense subsets and, hence, can have an arbitrary large positive Lebesgue measure. Within the abstract differential geometric context, it is shown that, starting with these nowhere dense differential algebras as a structure sheaf, one can recapture the exactness of the corresponding de Rham complex, and also obtain the short exponential sequence. These results are the two fundamental ingredients in developing differential geometry along classical, as well as abstract lines. Although the commutative framework is used here, one can easily deal with a class of singularities which is far larger than any other one dealt with so far, including in noncommutative theories.     

The L^2-Atiyah–Bott–Lefschetz theorem on manifolds with conical singularities: a heat kernel approach

Using an approach based on the heat kernel, we prove an Atiyah–Bott–Lefschetz theorem for the $L^2$ -Lefschetz numbers associated with an elliptic complex of cone differential operators over a compact manifold with conical singularities. We then apply our results to the case of the de Rham complex.     

Hochschild Homology of Twisted Tensor Products

We compute the Hochschild homology of some twisted tensor products of algebras, which are a natural generalization of the Ore extensions. We apply our result to the ring D _Q,P(X,/X) of differential operators of the multiparametric affine space, the ring of coordinates of the quantum symplectic 2v-dimensional space and the ring of coordinates of the quantum 2v-dimensional Euclidean space.     

扭化的Atiyah-Singer算子(I)

本文证明黎曼流表上的ｄｅ Ｒｈａｍ以及Ｓｉｇｎａｔｕｒｅ算子都同构于扭化的Ａｔｉｙａｈ－Ｓｉｎｇｅｒ算子。这两类算子的局部指数定理和局部Ｌｅｆｓｃｈｅｔｚ不动点公式都可以从扭化的Ａｔｉｙａｈ－Ｓｉｎｇｅｒ算子得到。     

扭化的Atiyah-Singer算子(Ⅰ)

本文证明黎曼流形上的deRham以及Signature算子都同构于扭化的Atiyah－Singer算子.这两类算子的局部指数定理和局部Lefschetz不动点公式都可以从扭化的Atiyah-Singer算子得到．     

On the Similarity of Some Differential Operators to Self-Adjoint Ones

The paper is devoted to the study of the similarity to self-adjoint operators of operators of the form , in the space with weight . As is well known, the answer to this problem in the case is positive; it was obtained by using delicate methods of the theory of Hilbert spaces with indefinite metric. The use of a general similarity criterion in combination with methods of perturbation theory for differential operators allows us to generalize this result to a much wider class of weight functions .     

On Quantized Algebra of Wess–Zumino Differential Operators at Roots of Unity

A quantum deformation of the algebra of differential operators is studied.     

On the Equivalence of Spectra of Linear Partial Differential Operators in Certain Function Spaces

For linear differential operators with coefficients of class C on ⁿ, we prove theorems on the simultaneous invertibility and equivalence of spectra in the Lebesgue space L ^p, Stepanov space M ^p, and in a particular Banach space V ^p L ^p, p 1     

Quantum sℓ(2) action on a divided-power quantum plane at even roots of unity

We describe a nonstandard version of the quantum plane in which the basis is given by divided powers at an even root of unity q = e^iπ/p. It can be regarded as an extension of the “nearly commutative” algebra ?[X, Y] with XY = (?1)^pYX by nilpotents. For this quantum plane, we construct a Wess-Zumino-type de Rham complex and find its decomposition into representations of the 2p ³ -dimensional quantum group $ \bar {\mathcal{U}} $ _q s?(2) and its Lusztig extension U _q s?(2); we also define the quantum group action on the algebra of quantum differential operators on the quantum plane.     

Hodge and Laplace–Beltrami Operators for Bicovariant Differential Calculi on Quantum Groups

For bicovariant differential calculi on quantum matrix groups a generalisation of classical notions such as metric tensor, Hodge operator, codifferential and Laplace–Beltrami operator for arbitrary k-forms is given. Under some technical assumptions it is proved that Woronowicz' external algebra of left-invariant differential forms either contains a unique form of maximal degree or it is infinite-dimensional. Using Jucys–Murphy elements of the Hecke algebra, the eigenvalues of the Laplace–Beltrami operator for the Hopf algebra (SL _q (N)) are computed.     

On a Class of Elliptic-Parabolic Equations on Unbounded Intervals

We study a class of degenerate elliptic second order differential operators acting on some polynomial weighted function spaces on [0,+[. We show that these operators are the generators of C ₀-semigroups of positive operators which, in turn, are the transition semigroups associated with right-continuous normal Markov processes with state space [0,+]. Approximation and qualitative properties of both the semigroups and the Markov processes are investigated as well. Most of the results of the paper depend on a representation of the semigroups we give in terms of powers of particular positive operators of discrete type we introduced and studied in a previous paper.