CONVERGENCE OF WEIGHTED AVERAGES OF MARTINGALES IN NONCOMMUTATIVE BANACH FUNCTION SPACES

Let x =(xn)n≥1 be a martingale on a noncommutative probability space (M,T) and (wn)n≥1 a sequence of positive numbers such that Wn =n∑k=1wk → ∞ as n → ∞.We prove that x =(xn)n≥1 converges in E(M) if an...     

PHASE RETRIEVAL OF TIME-LIMITED SIGNALS

The problem of reconstructing a signal ψ(x) from its magnitude |ψ(x)| is of considerable interest to engineers and physicists.This article concerns the problem of determining a time-limited signal f with period 2π when |f(eix)| is known for x ∈ [-π,π].It is shown that the conditions |g(eix)| = |f(eix)| and |g(ei(x+b))-g(eix)| = |f(ei(x+b))-f(eix)|,b = 2π,together imply that either g = wf or g = vf,where both w and v have period b.Furthermore,if 2bπ is irrational then the functions w and v reduce to some constants c1 and c2,respectively;if 2bπ is rational then w takes the form w=eiαB1(eix)B2(eix) and v takes the form ei(x2πN/b+α)B1(eix)B2(eix),where B1 and B2 are Blaschke products.     

THE SHARP ESTIMATE OF THE THIRD HOMOGENEOUS EXPANSION FOR A CLASS OF STARLIKE MAPPINGS OF ORDER α ON THE UNIT POLYDISK IN Cn

In this article,first,a sufficient condition for a starlike mapping of order α f(x) defined on the unit ball in a complex Banach space is given. Second,the sharp estimate of the third homogeneous expan...     

RESULTS ON A QUESTION OF ZHANG AND YANG

Abstract For a meromorphic function f,let N(l+1(r,1/f) denote the counting function of zeros of f of order l at least.Let f be a nonconstant meromorphic function,such that (N)(r,f) =S(r,f).Denote F =f...     

OSCILLATORY BEHAVIOR OF SOLUTIONS OF CERTAIN THIRD ORDER MIXED NEUTRAL DIFFERENCE EQUATIONS

The objective of this paper is to study the oscillatory and asymptotic properties of the mixed type third order neutral difference equation of the form △(an△2(xn+bnxn-τ1+cnxn+τ2))+qnxβn+1-σ1+pnxβn+1+σ2=0,where{an},{bn},{cn},{qn}and{pn} are positive real sequences,β is a ratio of odd positive integers,τ1,τ2,σ1 and σ2 are positive integers.We establish some sufficient conditions which ensure that all solutions are either oscillatory or converges to zero.Some examples are presented to illustrate the main results.