the aim of this paper is to extend results established by h. onoand t. kowalski regarding directly indecomposable commutative residuatedlattices to the non-commutative case. the main theorem states that a residuatedlattice a is directly indecomposable if and only if its boolean center b(a)is {0, 1}. we also prove that any linearly ordered residuated lattice and anylocal residuated lattice are d...

Let R be a countable, principal ideal domain which is not a field and A be a countable R-algebra which is free as an R-module. Then we will construct an א1-free R-module G of rank א1 with endomorphism algebra EndRG = A. Clearly the result does not hold for fields. Recall that an R-module is א1-free if all its countable submodules are free, a condition closely related to Pontryagin’s theorem. Th...

There are two infinitesimal (i.e., additive) versions of the K-theory of a field F : one introduced by Cathelineau, which is an F -module, and another one introduced by Bloch-Esnault, which is an F ∗module. Both versions are equipped with a regulator map, when F is the field of complex numbers. In our short paper we will introduce an extended version of Cathelineau’s group, and a complex-valued...

Following our approach to metric Lie algebras developed in a previous paper we propose a way of understanding pseudo-Riemannian symmetric spaces which are not semi-simple. We introduce cohomology sets (called quadratic cohomology) associated with orthogonal modules of Lie algebras with involution. Then we construct a functorial assignment which sends a pseudo-Riemannian symmetric space M to a t...

In this paper various representations of the exceptional Lie algebra G2 are investigated in a purely algebraic manner, and multi-boson/multi-fermion realizations are obtained. Matrix elements of the master representation, which is defined on the space of the universal enveloping algebra of G2, are explicitly determined. From this master representation, different indecomposable representations d...

We consider a polynomial ring S in n variables over a finite field k of characteristic p and an action of a finite group G on S by homogeneous linear substitutions. This is equivalent to taking the symmetric powers of an n-dimensional kG-module. We want to understand S as a kG-module in a manner as explicit as possible. The ideal solution would be to give a decomposition into indecomposable sum...

We prove that, for every r ≥ 2, the moduli space M X (r; c1, c2) of rank r stable vector bundles with Chern classes c1 = rH and c2 = 1 2 (3r 2 − r) on a nonsingular cubic surface X ⊂ P3 contains a nonempty smooth open subset formed by ACM bundles, i.e. vector bundles with no intermediate cohomology. The bundles we consider for this study are extremal for the number of generators of the correspo...

LetG be a finite p-group,K a field of characteristic p, and J the radical of the group algebra K[G]. We study modular representations using some new results of the theory of extensions of modules. More precisely, we describe the K[G]-modules M such that J2M = 0 and give some properties and isomorphism invariants which allow us to compute the number of isomorphism classes of K[G]-modulesM such t...

During the 2004-2005 academic year the VIGRE algebra research group at the University of Georgia computed the complexities of certain Specht modules S for the symmetric group Σd, using the computer algebra program Magma. The complexity of an indecomposable module does not exceed the p-rank of the defect group of its block. The Georgia group conjectured that, generically, the complexity of a Spe...