Syntheses of aliphatic polyesters catalyzed by lanthanide triflates

Polycondensations of 1,6‐hexane diol and sebacic acid were conducted in bulk with addition of a lanthanide triflate as acidic catalyst. With exception of promethium triflate all lanthanide triflates were studied. A particularly low molecular weight was obtained with neodym triflate and the best results with samarium triflate. With Sm(OTf)₃ weight average (M_w) values up to 65 kDa (uncorrected SEC data) were achieved after optimization of the reaction conditions. Comparison of these results with those obtained from bismuth, magnesium, and zinc triflates, on the one hand, and comparison with the acidities of all catalysts, on the other, indicates that the esterification mechanism involves complexation of monomer by metal ions. Preparation of multiblock copoly(ether ester)s failed due to insufficient incorporation of poly(tetrahydrofuran) diols. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 170–177, 2009     

Parameter estimation in nonlinear evolution equations

We develop a convergence theory for identifying parameters in a general class of nonau-

tonomous nonlinear evolution equations. An application of this theory to a nonlinear reaction diffusion equation is presented.     

Approximating fixed points of holomorphic mappings in the Hilbert ball

We approximate fixed points of holomorphic and ρ-nonexpansive self-mappings of the Hilbert ball using both continuous and discrete schemes.     

A projection method for solving nonlinear problems in reflexive Banach spaces

We study the convergence of an iterative algorithm for finding common fixed points of finitely many Bregman firmly nonexpansive operators in reflexive Banach spaces. Our algorithm is based on the concept of the so-called shrinking projection method and it takes into account possible computational errors. We establish a strong convergence theorem and then apply it to the solution of convex feasibility and equilibrium problems, and to finding zeroes of two different classes of nonlinear mappings.     

A Julia-Carathéodory theorem for hyperbolically monotone mappings in the Hilbert ball

We establish a Julia-Carathéodory theorem and a boundary Schwarz-Wolff lemma for hyperbolically monotone mappings in the open unit ball of a complex Hilbert space. The second author was partially supported by the Fund for the Promotion of Research at the Technion and by the Technion VPR Fund-B. and G. Greenberg Research Fund (Ottawa).