Let R be a commutative ring and S a multiplicatively closed subset of R having no zero divisors. The pair (.R, S) is said to be stable if the ring of fractions of R, S R, defined by S is a ring for which all finitely generated projective modules are free. For a stable pair (R, S) assume 2 is a unit in R and V is a free R-module of dimension > 3. This paper examines the action of a group automor...

in this paper we derive convergence theorems for an -nonexpansive mappingof a nonempty closed and convex subset of a complete cat(0) space for sp-iterative process and thianwan's iterative process.

A sequence is said to be k-automatic if the n term of this sequence is generated by a finite state machine with n in base k as input. A result due to Cobham states that if a sequence is both kand `-automatic and k and ` are multiplicatively independent, then the sequence is eventually periodic. Allouche and Shallit defined (R, k)-regular sequences as a natural generalization of k-automatic sequ...

In this note we prove a result which makes explicit the requirement that amultiplicatively-closed Markov model must form a Lie algebra (definitions will be provided). We consider continuous-time Markov chains and work under the general assumption that a model is determined by specifying a subset of rate matrices (or rate generators). These models are used in a wide array of scientific modelling...

Semiclassical limits of generic multiparameter quantized coordinate rings A = Oq(k) of affine spaces are constructed and related to A, for k an algebraically closed field of characteristic zero and q a multiplicatively antisymmetric matrix whose entries generate a torsionfree subgroup of k×. A semiclassical limit of A is a Poisson algebra structure on the corresponding classical coordinate ring...

Semiclassical limits of generic multiparameter quantized coordinate rings A = Oq(k ) of affine spaces are constructed and related to A, for k an algebraically closed field of characteristic zero and q a multiplicatively antisymmetric matrix whose entries generate a torsionfree subgroup of k. A semiclassical limit of A is a Poisson algebra structure on the corresponding classical coordinate ring...

let $r$ be an infinite ring. here we prove that if $0_r$ belongs to ${x_1x_2cdots x_n ;|; x_1,x_2,dots,x_nin x}$ for every infinite subset $x$ of $r$, then $r$ satisfies the polynomial identity $x^n=0$. also we prove that if $0_r$ belongs to ${x_1x_2cdots x_n-x_{n+1} ;|; x_1,x_2,dots,x_n,x_{n+1}in x}$ for every infinite subset $x$ of $r$, then $x^n=x$ for all $xin r$.

We construct a natural continuous linear extension operator for CWhitney fields (p finite) on closed o-minimal subsets, different from the Whitney’s one [W], based on the geometry of these sets. Introduction. By an o-minimal subset of an Euclidean space R we will mean a subset definable in any o-minimal structure on the ordered field of real numbers R (see [D, DM] for the definition and fundame...

We give an elementary proof that for a ring homomorphism A → B satisfying the property that every ideal in A is contracted from B the following property holds: for every chain of prime ideals p0 ⊂ . . . ⊂ pr in A there exists a chain of prime ideals q0 ⊂ . . . ⊂ qr in B such that qi ∩ A = pi. Mathematical Subject Classification (1991): 13B24. Let A and B be commutative rings and let φ : A → B b...