
第3 2 卷 第 1 期 上海师范大学学报
(
自然科学版
)
Vol.32
,
No.1
2 0 0 3 年 3 月 Journal of Shanghai Teachers U niversity
(
N atural S cien ce s
)
Mar.2003
Ishikaw a Iterative P rocess w ith E rrors for
a N ow C lass ofN onlinear E quations
of
-strongly A ccretive operators
ZENG Lu-chuan
,
LIANG Fang
(
M athem atics and Sciences C ollege
,
Shanghai Teachers U niversity
,
Shanghai200234
,
China
)
A bstract
:
Suppose thatX is an arbitrary real B anach space
,
H
:
X → X is Lipschitz continuous
,
T
:
X→Xisunifor-
m aly continuous
,
and H + T
:
X → X is -strongly accretive. It is show n that under suitable conditions
,
th e Is h ik a w a
iterative process with errors converges strongly to the unique solution ofthe equation H x + Tx = f. A related resultthat
deals with the approxim ation problem of fixed points of -hem icontractive opera to rs is a lso p rese n ted.
K ey w ords
:
arbitrary Banach space
;
-stro n ly a c cre tive o p e ra to r
;
-h em icontractive operator
;
Ishikawa iterative
p rocess w itherrors
CLC number
:
O 177.91
Documentcode
:
A
A r tic le ID
:
1000-5137
(
2003
)
01-0009-06
1 In tro d u c tio n an d P re lim in a rie s
R eceiv ed d ate
:
2002-05-12
Foundation item
:
S u p p o rte d b y b o th th e te a ch in g an d R e sea rch A w ard F u n d for O u tsta n d in g Y on g Teachers in H igher E du-
cation Istitutions of M O E and the N ational N atural Science Foundation
(
19801023
)
.
B iography
:
ZENG Lu-chuan
(
1965-
),
male
,
doctor
,
professor
,
M athem atics and Sciences C ollege
,
Sh anghai T eachers U ni-
versity.
LetX be an arbitrary realB anach space w ith norm ‖
·
‖ and dualX
*
. LetJ
:
X→2
X
*
be the norm alized du-
a lity m a p p in g d e fin e d b y
J
(
x
)
=
{
x
*
∈X
*
:
‖x
*
‖
2
=‖x‖
2
=‹x
,
x
*
›
}, (
1.1
)
where
,
‹
·,·
› denotes the generalized duality pairing. In the sequel
,
I denotes the identity operator on X . A n
operator T w ith dom ain D
(
T
)
and range R
(
T
)
in X is said to be strongly accretive if for allx
,
y∈D
(
T
),
there
existsaj
(
x-y
)
∈J
(
x- y
)
and a constantk > 0 such that
‹T x - T y
,
j
(
x-y
)
›≥K‖x-y‖
2
.
(
1.2
)
W ith ou t loss of gen erality w e m ay assu m e k ∈
(
0
,
1
)
. T is sa id to b e a c c re tiv e if fo r a ll x
,
y∈D
(
T
)
there exists
aj
(
x-y
)
∈J
(
x- y
)
such that‹T x - Ty
,
j
(
x-y
)
› ≥ 0. T is said to be -strongly accretive if for allx
,
y∈
D
(
T
)
there exists a j
(
x-y
)
∈J
(
x-y
)
and a strictly increasing function
:[
0
,
∞
)
→
[
0
,
∞
)
with
(
0
)
=
0 such that
‹T x - T y
,
j
(
x-y
)
›≥
(
‖x - y‖
)
‖x - y‖.
(
1.3
)