LetH∞ be the Banach algebra of all bounded analytic functions in the unit disk D. A function f ∈ H∞ is said to be universal with respect to the sequence ( z+zn 1+znz )n of noneuclidian translates, if the set {f( z+zn 1+znz ) : n ∈ N} is locally uniformly dense in the set of all holomorphic functions bounded by ||f ||∞. We show that for any sequence of points (zn) in D tending to the boundary th...

We study properties of a group, abelian group, ring, or monoid B which (a) guarantee that every homomorphism from an infinite direct product ∏ I Ai of objects of the same sort onto B factors through the direct product of finitely many ultraproducts of the Ai (possibly after composition with the natural map B → B/Z(B) or some variant), and/or (b) guarantee that when a map does so factor (and the...

Braided tensor products have been introduced by the author as a systematic way of making two quantum-group-covariant systems interact in a covariant way, and used in the theory of braided groups. Here we study infinite braided tensor products of the quantum plane (or other constant Zamolodchikov algebra). It turns out that such a structure precisely describes the exchange algebra in 2D quantum ...

In [4] Lawvere formalized the concept of an algebraic theory defined by operations and laws without existential quantifiers. Examples are the theories of monoids, groups, loops, rings, modules etc., whose axioms can be put into the required form; although not the theory of fields. The advantage of this approach lies in the unified treatment of a variety of universal constructions, especially th...

There has been a growing interest in constructing stationary measures with known multifractal properties. In an earlier paper, the authors introduced the multifractal products of stochastic processes MPSP and provided basic properties concerning convergence, nondegeneracy, and scaling of moments. This paper considers a subclass of MPSP which is determined by jump processes with i.i.d. exponenti...

We generalize and unify some aspects of the work of I. Daubechies, J.C. Lagarias [Linear Algebra Appl. 162 (1992) 227–263] on a set R of matrices with right-convergent-products (RCPs). We show that most properties of an RCP set R pass on to its compactification R (i.e., its closure in the matrix space). Results on finite RCP sets generally hold for compact RCP sets, among which is the existence...