fixed point iterations using infinite matrices - American Mathematical

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(iv). a. In the second case, there exists a subsequence such that lim ||x - f(x )|| = 0. ft fl. n». If x , x satisfy (i) of Z, then. "ft. "I. \\f(*nk>-n*n?W
TRANSACTIONSOF THE AMERICANMATHEMATICAL SOCIETY Volume 196, 1974

FIXED POINTITERATIONSUSINGINFINITEMATRICES BY

B. E. RHOADES ABSTRACT. Let £ be a closed,

space

X, /: E —»E. Consider

bounded,

the iteration

convex

subset

scheme defined

of a Banach

by x"« = xQ e E,

x n + ,l = 'ñx n ), x n = 2"* = na ,x., nal, where A is a regular weighted mean 0 nk k o er matrix. For particular spaces X and functions /we show that this iterative scheme converges

to a fixed point of /.

Let X be a normed linear space,

set of X, /: E —»£ possessing matrix.

Given the iteration

E a nonempty closed

bounded, convex sub-

at least one fixed point in E, and A an infinite

scheme

(1)

*o = *oeE'

(2)

*n+l=^*J»

« = 0,1,2,...,

fl

(3)

xn = F a nK,x.,« *-*Ä

«=1,2,

3, •••»

fe=0

it is reasonable

sufficient

to ask what restrictions

to guarantee

on the matrix A are necessary

that the above iteration

scheme converges

and/or

to a fixed point

of/. During the past few years several

iteration

schemes

this paper we establish

generalizations

point out some of the duplication An infinite

/. A matrix is called

sequences; triangular

if it is triangular

shall confine our attention

(4)

by the editors

of several

of infinite

matrices.

of these results

In

as well as

regular if it is limit preserving

over c, the

i.e., if x e c, xn —» /, then Aß(x)=

2fcan^xfc—»

if it has only zeros above the main diagonal,

and all of its main diagonal

to regular triangular

0-n*n?W

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