Showing papers in "Journal of Algebra in 2004"

TL;DR: In this article, Keller introduced a notion of quotient of a differential graded category modulo a full differential graded subcategory which agreed with Verdier's notion of the quotient for a triangulated classifier.

TL;DR: In this paper, it was shown that the edge chromatic number of a commutative ring R is equal to the maximum degree of R unless R is a complete graph of odd order.

TL;DR: In this paper, the Frobenius map is used to define a new invariant for a pair of a ring R and an ideal a⊂R, which is called the F-pure threshold c(a) of a, and study its properties.

TL;DR: In this article, it was shown that almost all homomorphisms from a Fuchsian group to alternating groups An are surjective, and this implies Higman's conjecture that every Fuchsians group surjects onto all large enough alternating groups.

TL;DR: In this article, an analogue of von Neumann's affiliated algebras for sofic groups over arbitrary fields was constructed, and the direct finiteness conjecture of Kaplansky's conjecture was settled.

TL;DR: In this paper, the authors introduce a new notion of Hopf algebroid, which is a 2-sided bialge-broid with a bijective antipode connecting the two, left and right handed, structures.

TL;DR: In this article, generalizations of the definitions of one-dimensional tilting and cotilting modules are considered. But they do not consider the notions of tilting modules of finite homological dimension.

TL;DR: In this article, the authors give a presentation of braid groups and pure braid group on surfaces and show some properties of surface pure Braid groups, and show that pure BRAB groups have some properties similar to those of pure pure bRAB.

TL;DR: In this article it was shown that for every Malcev algebra M there exists an algebra U(M) and a monomorphism ι:M→U(M), such that the image of M lies into the alternative center of U(m) and U(n) is a universal object with respect to such homomorphisms.

TL;DR: In this article, the authors show that the author's notion of Galois extensions of braided tensor categories gives rise to braided crossed G-categories, recently introduced for the purposes of 3-manifold topology.

TL;DR: For a normal projective variety X with a divisor class group Cl(X), this paper showed that TC(X) is a UFD for all Weil divisors of X contained in a fixed complete system of representatives of Cl.

TL;DR: In this paper, a Lie algebra is defined as a cohomology with values in a Lie-admissible module and the corresponding binary quadratic operads and their duality is studied.

TL;DR: In this paper, it was shown that every left morphic ring is right principally injective, and use this to characterize the left perfect, right and left uniserial local rings.

TL;DR: In this article, a general characteristic-free criterion for a rational map between projective varieties to be birational in terms of ideal-theoretic and modulo-theory conditions is presented.

TL;DR: In this article, a list of primitive permutation groups with a suborbit of length 4 is presented and a complete classification of vertex-primitive arc-transitive graphs of valency 3 and valency 4 is given.

TL;DR: The problem of describing the form of a bilinear map B : A × A → A satisfying B ( x, x ) x = x B (x, x ) for all x ∈ A is considered in this paper, where commutativity preserving maps and Lie isomorphisms of certain triangular algebras are determined.

TL;DR: In this paper, a G-twisted Zhu algebra AG,n(V) was introduced, which is a generalization of the axiomatization of AG, n(V), and the duality theorem of Schur-Weyl type holds for the actions of A α (G, S ) and VG on the direct sum of irreducible twisted V-modules in S as an application of the theory of AG.

TL;DR: In this article, the generators of the ideals of graded polynomial identities of the algebra of n × n upper triangular matrices over an infinite field were described and linear bases of the corresponding relatively free graded algebras were obtained.

TL;DR: In this paper, the Murphy basis of the Ariki-Koike algebras was used to construct a complete set of primitive idempotents for semisimple and q ≥ 1.

TL;DR: In this paper, the authors classify irreducible integrable modules for multi-loop algebras and prove that any such module is isomorphic to the one in this paper.

TL;DR: In this article, it was proved that a quasifinite irreducible B -module is a highest or lowest weight module and furthermore, the unitary ones are trivial.

TL;DR: In this article, the Nash problem on arc families is affirmedatively answered for a toric variety by Ishii and Kollar's paper, which also shows the negative answer for general case.

TL;DR: The notion of generalized tilting modules over arbitrary rings was introduced in this paper, where it was shown that the Auslander's Gorenstein property can be generalized over noetherian rings.

TL;DR: In this article, the shape of the automorphism group of V L + is determined when L is isomorphic to an even unimodular lattice without roots, 2 R for an irreducible root lattice R of type ADE and the Barnes-Wall lattice of rank 16.

TL;DR: In this article, the concept of Arf system of generators for an Arf numerical semigroup is introduced and studied, which allows us to arrange the set of all arf numerical semiigroups in a binary tree, and enables us to compute the Arf closure of a given numerical semiigroup.

TL;DR: In this article, a general construction of a fractional skew monoid ring S op ∗ α A∗ α T is given, extending the usual constructions of skew group rings and of skew semigroup rings.

TL;DR: In this article, the Composition-Diamond Lemma for associative conformal algebras is proved to be solvable for some homogeneous conformal algebraic structures, while it is unsolvable in general.

TL;DR: In this paper, the influence of π-quasinormality of maximal subgroups of Sylow subgroups on the structure of finite groups was investigated and the main theorems were as follows:

TL;DR: In this paper, it was shown that an ideal has generators if and only if it lies on the face of a simplex of codimension $k, and that there is a bijection between the ad-nilpotent ideals and the integral points of the simplex with rational vertices.

TL;DR: In this paper, it was shown that there are 3p2+39p+344+24gcd(p−1,3)+11gcdgc(p −1,4)+2gccdc( p−1.5) isomorphism types of groups and nilpotent Lie rings with order p6 for every prime p⩾5.