We study a class of infinite dimensional Lie algebras called generalized Witt algebras (in one variable). These include the classical Witt algebra and the centerless Virasoro algebra as important examples. We show that any such generalized Witt algebra is a semisimple, indecomposable Lie algebra which does not contain any abelian Lie subalgebras of dimension greater than one. We develop an inva...

We prove that the abelian K-surfaces whose endomorphism algebra is an indefinite rational quaternion algebra are parametrized, up to isogeny, by the K-rational points of the quotient of certain Shimura curves by the group of their Atkin-Lehner involutions. To cite this article: X. Guitart, S. Molina, C. R. Acad. Sci. Paris, Ser. I

An artin algebra A is said to be CM-finite if there are only finitely many, up to isomorphisms, indecomposable finitely-generated Gorenstein-projective A-modules. We prove that for a Gorenstein artin algebra, it is CM-finite if and only if every its Gorenstein-projective module is a direct sum of finitely-generated Gorenstein-projective modules.

Purpose This study aims to find all subalgebras up conjugacy in the real simple Lie algebra so(3,1) . Design/methodology/approach The authors use Algebra techniques inequivalent of dimensions....

These are notes for a lecture given at Ohio University on June 3, 2006. An important topic in commutative algebra is the Rees algebra of an ideal in a commutative ring. The Rees algebra encodes a lot of information about the ideal and corresponds geometrically to a blow-up. One can represent the Rees algebra as the quotient of a polynomial ring by an ideal. This ideal is generated by the defini...

Let [Formula: see text] be a text]-dimensional quantum polynomial algebra, and central regular element. The quotient algebra is called noncommutative conic. For conic text], there finite-dimensional which determines the singularity of text]. In this paper, we mainly focus on such that its quadratic dual commutative, equivalent to say, determined by symmetric superpotential. We classify these co...

We characterize the structure of a seven-dimensional Lie algebra with non-trivial center endowed closed G$_2$-structure. Using this result, we classify all unimodular algebras admitting G$_2$-structures, up to isomorphism, and show that six them arise as contactization symplectic algebra. Finally, prove every semi-algebraic soliton on must be expanding, determine dimension at least two admit so...