(One-value) graph magma algebras are algebras having a basis B = V boolean OR {1} such that, for all u,v is an element of V, uv is an element of {u,0}. Such bases induce graphs and, conversely, certain types of graphs ...

In this work we present experimental results that allow to characterize different solid modifications found in o-chlorohalobenzenes. Three disordered phases have been found in o-chlorobromobenzene. The stable phase at ...

Let f: A → B be a ring homomorphism of not necessarily unital rings and I A an ideal which is mapped by f isomorphically to an ideal of B. The obstruction to excision in K-theory is the failure of the map between relative ...

Let G be a group and F a nonempty family of subgroups of G, closed under conjugation and under subgroups. Also let E be a functor from small Z-linear categories to spectra, and let A be a ring with a G-action. Under mild ...

Let X be a projective smooth curve over an algebraically closed field k. Let K = k(X) the field of rational functions on X and O_X,p the regular local ring on p, for p in X. Since X is smooth and dim X = 1, the completion ...

The 12-dimensional Fomin-Kirillov algebra FK3 is defined as the quadratic algebra with generators a, b and c which satisfy the relations a2=b2=c2=0 and ab+bc+ca=0=ba+cb+ac. By a result of A. Milinski and H.-J. Schneider, ...

Given two groups such that their Tables of Marks are isomorphic, their Burnside Rings are also isomorphic. But given two non-isomorphic groups, with non-isomorphic Tag Charts, are their Burnside Rings isomorphic, or not? ...

We study the Gelfand Kirillov conjecture for some algebras and rings, we use similar tools for studying the ring of fractions of skew PBW extensions, establishing isomorphisms between algebras and rings. Particular cases ...

For a twisted partial action e of a group G on an (associative non-necessarily unital) algebra A over a commutative unital ring k, the crossed product A x(Theta) G is proved to be associative. Given a G-graded k-algebra B ...