蘭 溪, 孫玉祥
(1.吉林油田第十一中學(xué),吉林松原 138000; 2.北華大學(xué)師范學(xué)院數(shù)學(xué)系代數(shù)教研室,吉林 132013)
非奇異H-矩陣的實(shí)用判定
蘭 溪1, 孫玉祥2
(1.吉林油田第十一中學(xué),吉林松原 138000; 2.北華大學(xué)師范學(xué)院數(shù)學(xué)系代數(shù)教研室,吉林 132013)
H-矩陣在許多領(lǐng)域中都起著非常重要的作用,例如數(shù)學(xué)分析、矩陣?yán)碚摗?shù)學(xué)經(jīng)濟(jì)學(xué)、控制論等.但是在實(shí)際運(yùn)用中判定H-矩陣卻十分困難.本文類似于文[4],均以α-對(duì)角占優(yōu)理論為基礎(chǔ),給出H-矩陣的若干實(shí)用判定,改進(jìn)了文[3]的相應(yīng)結(jié)果.
非奇異H-矩陣;廣義嚴(yán)格對(duì)角占優(yōu)矩陣;廣義嚴(yán)格α-對(duì)角占優(yōu)矩陣
眾所周知,廣義嚴(yán)格對(duì)角占優(yōu)矩陣就是非奇異H-矩陣.因非奇異H-矩陣主對(duì)角元素非零,所以本文假定所涉及矩陣主對(duì)角元非零,設(shè)A=(aij)∈n×n為n階復(fù)方陣,N={1,2,…,n}.設(shè)A的比較矩陣M(A)=(mij)∈R Rn×n為n階實(shí)方陣,其中
則稱為嚴(yán)格對(duì)角占優(yōu)矩陣,記為A∈D.若存在一組正數(shù)di(i=1,2,…,n),使得
則稱A為廣義嚴(yán)格對(duì)角占優(yōu)矩陣,記為A∈H.
定義2 設(shè)A=(aij)∈n×n,若存在α∈(0,1),使?i∈N N,有
則稱A為嚴(yán)格α-對(duì)角占優(yōu)矩陣,記A∈D(α).若存在一組正數(shù)di(i=1,2,…,n),使
則稱A為廣義嚴(yán)格α-對(duì)角占優(yōu)矩陣,記為A∈D*(α).
引理1[1]設(shè)A=(aij)∈n×n,則A是廣義嚴(yán)格對(duì)角占優(yōu)矩陣當(dāng)且僅當(dāng)A是廣義嚴(yán)格α-對(duì)角占優(yōu)矩陣.
引理2[2]設(shè)A=(aij)∈n×n,B=M(A)+MT(A).若B是廣義嚴(yán)格對(duì)角占優(yōu)矩陣,則A是廣義嚴(yán)格對(duì)角占優(yōu)矩陣.
定理設(shè)A=(aij)∈C Cn×n.若存在α∈(0,1),使
則B為廣義嚴(yán)格α-對(duì)角占優(yōu)矩陣,由引理1知B為廣義嚴(yán)格對(duì)角占優(yōu)矩陣,再由引理2知A∈H.
有了上述定理我們就很容易判定高階矩陣是否為非奇異H-矩陣.看下面的例子:
[1] Sun Yu-Xiang.An improvement on a theorem by Ostrowski and its applications[J].North-eastern Math,1991,7(4):497-502.
[2] Berman A and Plemmons R J.Nonnegative matrices in the mathematical sciences[M].New York:Academic,1979.
[3] 徐仲,陸全.判定廣義嚴(yán)格對(duì)角占優(yōu)矩陣的一組充分條件[J].工程數(shù)學(xué)學(xué)報(bào),2001,18(3):11-15.
[4] 謝清明.判定廣義對(duì)角占優(yōu)矩陣的幾個(gè)充分條件[J].工程數(shù)學(xué)學(xué)報(bào),2006,23(4):757-760.
Practical Criterion for Nonsingular H-Matrices
LAN Xi1, SUN Yu-xiang2
(1.No.11 Senior Middle School of Jilin Oil Field,Songyuan,Jilin 138000,China;
2.Department of Mathematics,Normal Science College,Beihua University,Jilin 132013,China)
H-matrices play a very important role in many fields like Numerical Analysis,Matrix theory,Mathematical Economics,Control theory,etc.But it is difficult to judge H-matrices in practice.In this paper,we give some practical criterions for nonsingular H-matrices abase on the theory ofα-diagonally dominant matrices,it is similar to[4].And improve the results of[3].
nonsingular H-matrices;generalized strictly diagonally dominant matrix;generalized strictlyα-diagonally dominant matrix
O151.21
A
1672-1454(2010)05-0109-03
2008-06-16