The isomorphism problem for group algebras over a field with arbitrary characteristic of some special classes of torsion-free non-abelian groups is explored. Specifically, the following are proved: Suppose F is a field and G is a torsion-free group with centre C(G) such that FG ∼= FH as F -algebras for any group H . Then it is shown that H is torsion-free (provided that FG is without zero divis...

Let X and Y be compact Hausdorff spaces, and E, F be Banach lattices. Let C(X,E) denote the Banach lattice of all continuous E-valued functions on X equipped with the pointwise ordering and the sup norm. We prove that if there exists a Riesz isomorphism Φ : C(X,E) → C(Y, F ) such that Φf is non-vanishing on Y if and only if f is non-vanishing on X, then X is homeomorphic to Y , and E is Riesz i...

An equivariant Thom isomorphism theorem in operator K-theory is formulated and proven for infinite rank Euclidean vector bundles over finite dimensional Riemannian manifolds. The main ingredient in the argument is the construction of a non-commutative C-algebra associated to a bundle E → M , equipped with a compatible connection ∇, which plays the role of the algebra of functions on the infinit...

In this paper, we introduce and study notions like state-\linebreak distinguishability, input-distinguishability and output completeness of states of a crisp deterministic fuzzy automaton. We show that for each crisp deterministic fuzzy automaton there corresponds a unique (up to isomorphism), equivalent distinguished crisp deterministic fuzzy automaton. Finally, we introduce two axioms related...

Let be a nite dimensional hereditary algebra over a nite eld k; H(() and C(() be respectively the Hall algebra and the composition algebra of ; P be the isomorphism classes of nite dimensional-modules and I the isomorphism classes of simple-modules. We deene and , 2 P, to be the right and left derivations of H(() respectively. By using these derivations and the action of the braid group on the ...

Let C be any class of graphs. A graph G is C-ultrahomogeneous if every isomorphism between induced subgraphs belonging to C extends to an automorphism of G. We study graphs that are K∗-ultrahomogeneous, where K∗ is the class of complete graphs. We also explicitly classify the graphs that are tK∗-ultrahomogeneous, where tK∗ is the class of disjoint unions of complete graphs.

Rooth (1992) and Fiengo and May (1994) argue that elliptical structures are subject to both a semantic and a syntactic parallelism requirement. Pseudosluicing, where an elliptical cleft takes a non-cleft as its antecedent, pose a problem for the idea that there is a syntactic parallelism requirement. In this talk, we will look at Spanish data (building on the analysis of Rodrigues et al. 2008) ...

The isomorphism problem is neither known to be NP-complete nor polynomial. Yet it is crucial for managing large conceptual graph sets. In order to speed up the conceptual graph isomorphism test, we associate to graphs a textual code that is invariant under isomorphism: a structural or ltering code. The structural code of a given graph is based on the computation by a structural function of an i...

Many applications can be m o deled a s s u b graph iso-morphism problems, which are g e n e r ally NP-complete. This paper presents an algorithm that is suited for hardware implementation. The prototype a c celerator that operates at 16.5 MHz on a Lucent ORCA 2C15A FPGA outperforms the software implementation of Ullmann's algorithm on a 400 MHz Pentium II by 10 times in the best case. 1 Subgrap...