The Universal Multiplicative Envelope of the Free Malcev Superalgebra on One Odd Generator

A base of the universal multiplicative envelope for the free Malcev superalgebra on one odd generator is constructed. Some corollaries for central skew-symmetric elements in free Malcev and free alternative algebras are obtained. In particular, the Malcev Grassmann algebra is constructed.     

Malcev superalgebras with trival nucleus

The nucleus of a Malcev superalgebra M measures how far it is from being a Lie superalgebraM being a Lie superalgebra if and only if its nucleus is the whole M. This paper is devoted to study Malcev superalgebras in the opposite direction, that is, with trivial nucleus. The odd part of any finite-dimensional Malcev superalgebra with trivial nucleus is shown to be contained in the solvable radical. For algebraically closed fields, any such superalgebra splits as the sum of its solvable radical and a semisimple Malcev algebra contained in the even part, which is a direct sum of copies of sl(2, F) and the seven-dimensional simple non-Lie Malcev algebra, obtained from the Cayley-Dickson algebra.     

The Free Alternative Nil-Superalgebra of Index n on One Odd Generator

A base of the free alternative nil-superalgebra of index n, for n ≥ 3, on one odd generator is constructed. In particular, its index of solvability is computed. As a corollary over a field of characteristic zero an infinite family of solvable alternative algebras which are not associative of arbitrary big solvability index with explicit multiplication table is obtained.     

A NEW QUASITRIANGULAR HOPFSUPERALGEBRA AND ITS UNIVERSAL R-MATRIX

Thequantumdouble(QD)theory['-3],whichwasfirstproposedbyDrinfeld[1],isaquitepowerfultoolinconstructingsolutionsofthequantumYang-Barerequations(QYBE).ThecoreoftiletheoryliesinthefaCtthatfromagivenHopf(super)ajgebraonecallgetauniquequasitriangularHopf(super)algebrawithauniversalRmatrix.Further,onemayobtainthenumericalsolutionsofQYBEbystudyingtherepresentations,especially,thefinite-dimensionalrepresentationsofQD.Thus,itisinterestingtoopennewwaysforconstructingQD's.Astepinthisdirectionhasb…     

Graphs isomorphic to their maximum matching graphs

The maximum matching graph M（G） of a graph G is a simple graph whose vertices are the maximum matchings of G and where two maximum matchings are adjacent in M（G） if they differ by exactly one edge. In this paper, we prove that if a graph is isomorphic to its maximum matching graph, then every block of the graph is an odd cycle.     

Moduli spaces ℳ<Subscript>2,1</Subscript> and ℳ<Subscript>3,1</Subscript>

The cell structure of the spaces ℳ_2,1 and ℳ_3,1 is considered. These are the spaces of complex curves of genus 2 and 3 with one marked point. For the space ℳ_2,1, nine cells of the highest dimension 8 are described and their adjacency is studied. For the space ℳ_3,1, a list of all 1726 cells of the highest dimension 14 (with orientation) is obtained. The list of adjacent couples of cells is also obtained. These lists can be found on the web.     

Transformations with highly nonhomogeneous spectrum of finite multiplicity

This paper studies a spectral invariant ℳ _T for ergodic measure preserving transformationsT called theessential spectral multiplicities. It is defined as the essential range of the multiplicity function for the induced unitary operatorU _T. Examples are constructed where ℳ _T is subject only to the following conditions: (i) 1∈ℳ _T , (ii) lcm(n, m)∈ℳ _T wherevern, m ∈ ℳ _T , and (iii) sup ℳ _T <+∞. This shows thatD _T, definedD _T=card ℳ _T , may be an arbitrary positive integer. The results are obtained by an algebraic construction together with approximation arguments. This research was partially supported by NSF grant MCS 8102790.     

Clifford-Hermite-monogenic operators

In this paper we consider operators acting on a subspace ℳ of the space L ₂ (ℝ^m; ℂ_m) of square integrable functions and, in particular, Clifford differential operators with polynomial coefficients. The subspace ℳ is defined as the orthogonal sum of spaces ℳ_s,k of specific Clifford basis functions of L ₂(ℝ^m; ℂm). Every Clifford endomorphism of ℳ can be decomposed into the so-called Clifford-Hermite-monogenic operators. These Clifford-Hermite-monogenic operators are characterized in terms of commutation relations and they transform a space ℳ_s,k into a similar space ℳ_s′,k′. Hence, once the Clifford-Hermite-monogenic decomposition of an operator is obtained, its action on the space ℳ is known. Furthermore, the monogenic decomposition of some important Clifford differential operators with polynomial coefficients is studied in detail.     

Self-injective rings and linear (weak) inverses of linear finite automata over rings

LetR be a finite commutative ring with identity and τ be a nonnegative integer. In studying linear finite automata, one of the basic problems is how to characterize the class of rings which have the property that every (weakly) invertible linear finite automaton ℳ with delay τ over R has a linear finite automaton ℳ′ over R which is a (weak) inverse with delay τ of ℳ. The rings and linear finite automata are studied by means of modules and it is proved that *-rings are equivalent to self-injective rings, and the unsolved problem (for τ=0) is solved. Moreover, a further problem of how to characterize the class of rings which have the property that every invertible with delay τ linear finite automaton ℳ overR has a linear finite automaton ℳ′ over R which is an inverse with delay τ′ for some τ′⩾τ is studied and solved. Project supported by the National Natural Science Foundation of China(Grant No. 69773015).     

Stable windings on hyperbolic surfaces

Let ℳ be a geometrically finite hyperbolic surface with infinite volume, having at least one cusp. We obtain the limit law under the Patterson-Sullivan measure on T ¹ℳ of the windings of the geodesics of ℳ around the cusps. This limit law is stable with parameter 2δ− 1, where δ is the Hausdorff dimension of the limit set of the subgroup Γ of M?bius isometries associated with ℳ. The normalization is t ^{−1/(2δ−1)}, for geodesics of length t. Our method relies on a precise comparison between geodesics and diffusion paths, for which we need to approach the Patterson-Sullivan measure mentioned above by measures that are regular along the stable leaves. Received: 8 October 1999 / Revised version: 2 June 2000 / Published online: 21 December 2000     

Structure of some Unital Simple Jordan Superalgebras with Associative Even Part

Studying the unital simple Jordan superalgebras with associative even part, we describe the unital simple Jordan superalgebras such that every pair of even elements induces the zero derivation and every pair of two odd elements induces the zero derivation of the even part. We show that such a superalgebra is either a superalgebra of nondegenerate bilinear form over a field or a four-dimensional simple Jordan superalgebra.     

Distributivity conditions for lattices of dominions in quasivarieties of Abelian groups

Let ℳ be any quasivariety of Abelian groups, L_q(ℳ) be a subquasivariety lattice of ℳ, dom _G ^ℳ be the dominion of a subgroup H of a group G in ℳ, and G/dom _G ^ℳ (H) be a finitely generated group. It is known that the set L(G, H, ℳ) = {dom _G ^N (H)| N ∈ L_q(ℳ)} forms a lattice w.r.t. set-theoretic inclusion. We look at the structure of dom _G ^ℳ (H). It is proved that the lattice L(G,H,ℳ) is semidistributive and necessary and sufficient conditions are specified for its being distributive. __________ Translated from Algebra i Logika, Vol. 45, No. 4, pp. 484–499, July–August, 2006.     

Quantum superalgebra osp(2∥1)

A quantum deformation of the simplest rank-one orthosymplectic Lie superalgebra is constructed in two ways: by changing the anticommutatoin relations of the odd generators [V₊, V_–] ~ shH, and by using a constant triangular R-matrix which is an appropriate limit of the R-matrix of the supersymmetric sine-Gordon model. A relationship between these two approaches is established. The matrix elements of the odd generators and an analog of the Casimir operator are found for finite-dimensional representations.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 169, pp. 95–106, 1988.     

Shapovalov determinant for loop superalgebras

For the Kac-Moody superalgebra associated with the loop superalgebra with values in a finite-dimensional Lie superalgebra g, we show what its quadratic Casimir element is equal to if the Casimir element for g is known (if g has an even invariant supersymmetric bilinear form). The main tool is the Wick normal form of the even quadratic Casimir operator for the Kac-Moody superalgebra associated with g; this Wick normal form is independently interesting. If g has an odd invariant supersymmetric bilinear form, then we compute the cubic Casimir element. In addition to the simple Lie superalgebras g = g(A) with a Cartan matrix A for which the Shapovalov determinant was known, we consider the Poisson Lie superalgebra poi(0|n) and the related Kac-Moody superalgebra. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 156, No. 3, pp. 378–397, September, 2008.     

Essentiality and injectivity relative to sequential purity of acts

For a class ℳ of monomorphisms of a category, mathematicians consider different types of essentiality, depending on ℳ. In this paper, considering the category of acts over a semigroup, we first briefly study the class ℳ _p of a certain kind of pure monomorphisms, in a manner borrowed from V. Gould, to be called sequentially pure. Then, we study in detail three kinds of essentiality with respect to this class, and give some useful criteria to get (internal) characterizations (in terms of elements) for essentialities. Finally, the relations between injectivity, essentiality, retractness, and injective hulls, all with respect to the class of sequentially pure monomorphisms, are investigated. The second author is thankful to Iran National Science Foundation (INSF) for their financial support.     

Quantum commutative algebras and their duals

If an algebraA is quantum commutative with respect to the action of a quasitriangular Hopf algebraH, then the monoidal structure on the category_H ^ℳ of modules overH induces a rnonoidal structure on the category_A#H ^ℳ of modules over the associated smash productA # H. The condition under which the braiding structure of_H ^ℳ induces a braiding structure on_A#H ^ℳ is further investigated. Dually, the notion of quantum cocommutativity is introduced, and similar result in this dual situation is obtained.     

Two constructions of oriented matroids with disconnected extension space

The extension space ℰ(ℳ) of an oriented matroid ℳ is the poset of all one-element extensions of ℳ, considered as a simplicial complex. We present two different constructions leading to rank 4 oriented matroids with disconnected extension space. We prove especially that if an elementf is not contained in any mutation of a rank 4 oriented matroid ℳ, then ℰ(ℳ\f) contains an isolated point. A uniform nonrealizable arrangement of pseudoplanes with this property is presented. The examples described contrast results of Sturmfels and Ziegler [12] who proved that for rank 3 oriented matroids the extension space has the homotopy type of the 2-sphere.     

On Right Alternative Superalgebras

Simple right alternative superalgebras which have a simple algebra as even part and, as odd part, an irreducible bimodule over the even part are investigated. Under these conditions, superalgebras with one dimensional even part are classified, as well as superalgebras having M ₂(F) as even part and a unital irreducible bimodule over M ₂(F) of dimension less than or equal to 6 as odd part. It is shown that there is only a unique non alternative simple right alternative superalgebra of the first type and, for the second type, there is a infinite family depending on a single parameter.