8 „
1 :n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
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A, B nz .
1.1 “o( .
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1.2 UkfmCX .
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1.3
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1.4 § AX = XB ? .
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1.5 r A L« A ı“.
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1.6
1.7 A«? .
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A ı“ Jordan IO/ .
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1.7.1 1 .
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1.7.2 .
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1.7.3 " .
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1.7.4 Gram .
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1.7.5 .
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1.7.6 Hilbert .
1.7.7 5 .
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1
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7
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8
. 11
. 14
. 18
. 20
. 20
. 21
. 22
. 22
. 23
. 24
. 25
2 flK8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
2.1 flK .
2.2 ) .
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. 29
. 32
1
1
:n
1.1 “o(
{“· r(AB) 6 min{r(A), r(B)}, r(A + B) 6 r(A) + r(B), øp
2y†. y†“{k—CA{, {3ıŒ
·B. A^{·e¡ø“:
XJ
(
)
M =
A 0
C B
øp A, B ·, @o r(M ) > r(A) + r(B).
y†g··kr A, B z⁄IO/: P1AQ1 = Er, P2BQ2 = Es, @o
)
(
)(
)(
(
)
0
P1
0 P2
0
Er
D Es
,–^ Er ZK D c r , ^ Es ZK D s 1, M C⁄øf
0
P2CQ1 Es
0
Q1
0 Q2
A 0
C B
=
(
=
)
Er 0
0
0
0
∗
0
0 Es
Er
M =
ø(.
3y†k’“, ˜g··lOØu, z⁄n‰en
'‹, 5A^¡ø(.
Frobenius “y†
A ·Œ F m × n , B · n × k , C · k × s , K
y†:
(
)
r(AB) + r(BC) 6 r(ABC) + r(B)
)
(
)
0 −ABC
BC
B
AB 0
B BC
−−−−−−−−−−−−−−−→
1mƒ– ¡C \1
(
−−−−−−−−−−−−−−−→
11ƒ– ¡A \11
0 −ABC
B
0
1
CHAPTER1. :n
1.1. “o(
’(.
5¿øp¢·r¢g·“X”5. 3œAT·l
(
)
ABC 0
B
0
u5C. /“c¡nU⁄øf.
pnK
flflflKKK 1:
(2005fi˘) A ·Œ F n m5C, ƒy
A3 = I ⇔ r(I − A) + r(I + A + A2) = n
y†: 5¿3 u(x), v(x) ƒ u(x)(1 − x) + v(x)(1 + x2 + x) = 1, ˜
2n (
I − A
(
)
0
I − A u(A)(I − A)
I + A + A2
0
)
(
−−−−−−−−−−−−−−−→
1ƒ– u(A) \1
(
I − A
I + A + A2
)
)
0
I
)
I
I + A + A2
(
0
A3 − I
0
I
A3 − I 0
0
I + A + A2
−−−−−−−−−−−−−−−→
11ƒ– v(A) \1
−−−−−−−−−−−−−−−→
1ƒ– A ¡ I \1
−−−−−−−−−−−−−→
me I + A + A2
⁄–ø· n = A3 − I = 0, øy†.
(2006fi˘) A, B · n , y†
flflflKKK 2:
r(A − ABA) = r(A) + r(I − BA) − n
(
)
0
A
BA I − BA
y†:
(
)
(
0
A
0 I − BA
−−−−−−−−−→
1\1
A A
BA I
−−−−−−−−−−−−−−−→
11ƒ– ¡A \11
)
−−−−−−−−−−−−−−−→=
11ƒ– B \11
)
)
(
(
A − ABA 0
BA
I
A − ABA 0
I
0
−−−−−−−−−−−−−−−−→
1mƒ– ¡BA \1
–C·—C, –C. l“⁄Æ.
2
CHAPTER1. :n
1.1. “o(
flflflKKK 3:
(2007fi˘) A, B · n v AB = BA. ƒy
r(A) + r(B) > r(A + B) + r(AB)
y†: X ·g5§| AX = 0 )m, Y ·g5§| BX = 0
)m, Z ·g5§| ABX = BAX = 0 )m, W ·g5
§| (A + B)X = 0 )m, @o•k X ⊂ Z, Y ⊂ Z. l X + Y ⊂ Z.
X ∩ Y ⊂ W . dŒœ“,
dimX + dimY = dimX ∩ Y + dim(X + Y ) 6 dimW + dimZ
l
n − r(A) + n − r(B) 6 n − r(A + B) + n − r(AB)
= r(A) + r(B) > r(A + B) + r(AB).
5: øK8–^—C5, ·w,A{{’.
ÆSK
flflflKKK 1: A, B ·Œ F n v AB = BA = 0, r(A) = r(A2), ƒy
r(A + B) = r(A) + r(B)
e¡'O^C{A{y†, §’3uØ
r(A) = r(A2) ø^|^.
Cy†: g·: y† r(A + B) > r(A) + r(B) =. ^P{, l
(
A + B 0
0
0
(
)
)
B ∗
0 A
u, ˇL—Cz/X
, (. 3Cck5¿::
(1)du A2 · A 5|, ⁄– r(A) = r(A2) ‘† A
| A2 |·d, · A – A2
5L«5. αi · A 1 i , @o5§| A2X = αi k) Xi, -
n × n P = (X1, X2,··· , Xn), @o A2P = A.
(2)g( r(A) = r(A2) k r(A) = r(A2) = r(A3) = ···
y†: 3 Frobenius “
r(B) + r(ABC) > r(AB) + r(BC)
3
CHAPTER1. :n
1.1. “o(
¥- B = C = A J(.
e¡?1C:(
)
A + B 0
0
0
−−−−−−−−−−−−−−→
1mƒ– A \1
−−−−−−−−−−−−−−−→
1mƒ– ¡P \1
)
−−−−−−−−−−−−−−→=
11ƒ– A \11
)
A + B A2
A3
(
(
A2
B A2
0 A3
(
)
A + B 0
0
A2
l r(A + B) > r(B) + r(A3) = r(B) + r(A), y.
A{: ø{g·5gØ^ r(A2) = r(A) ,«). ˜ky†
e¡n:
r(A2) = r(A) ⇒ V = KerA ⊕ ImA.
y†: η1, η2, ··· , ηn¡r · KerA |˜, Aε1, Aε2, ··· , Aεr · ImA |
˜. •I‘†
η1,··· , ηn¡r, Aε1,··· , Aεr
⁄ V |˜=. ø KerA + ImA ·, Œ· n, n
y†.
" c1,··· , cn ƒ
n¡r∑
ciηi +
ciAεj = 0
(∗)
@o3>^ A ^:
i=1
· A2X = 0 AX = 0 )m·, ⁄–
A2(
ciεj) = 0
A(
ciεj) = 0
=
£(∗)“
j=1
j=1
r∑
r∑
r∑
r∑
n¡r∑
j=1
j=1
ciAεj = 0
ciηi = 0
i=1
4
CHAPTER1. :n
1.1. “o(
⁄– ci ·0, ny.
⁄Ky†: Jy KerA ImA · B Cfm. B 3
ImA ·0. ⁄–3˜ η1, ··· , ηn¡r, Aε1, ··· , Aεr e A, B /X
(
)
(
A =
0
0
0 A1
B =
B1 0
0
0
y3 r(A + B) = r(A) + r(B) ·Øw,.
5: XJØ$E|vG{, øK8–w5. –b A
· Jordan IO/, @o r(A) = r(A2) ‘† A 0AØA Jordan ‹·
. l A /X
)
)
A1 0
0
0
A1
(
=
)
0
...
0
(
0
B1
0 B2
øp A1 ·_. AB = BA = 0 ‘† B /X
(ø^. ˇ A1 vkA0, ⁄– A 7,·OØ.
[„1.4) øp A1B1 = B1A1 = 0. du A1 _, ⁄– B1 = 0. ø
y†.
flflflKKK 2: A, B n , ƒy r(A + B) = r(A) + r(B) ¿^·3_
P , Q ƒ
(
(
)
)
P AQ =
P BQ =
Er 0
0
0
0
0
0 Es
¥ r, s 'O· A, B , r + s 6 n.
y†: y75. –k P , Q ƒ
(
)
P AQ =
Er 0
0
0
⁄–b A ·IO/, e¡y†–^—CUC A /G, r B
C⁄/G.
(
)
B =
B1 B2
B3 B4
5
)
1.1. “o(
CHAPTER1. :n
(
A + B =
(
s = r(B) > r
Er + B1 B2
B4
)
B3
> r(A + B) − r = s
1·ˇl A + B ¥c r ı~ r.
⁄–
lkC
n
⁄–k1C
(
B2
B4
)
)
B2
B4
r
(
= r(B)
(
B =
B1 B2
B3 B4
(
C−−−−→
)
0 B2
0 B4
r
(
0
0
B3 B4
)
= r(B)
(
B =
B1 B2
B3 B4
1C−−−−→
)
)
)
B =
B1 B2
B3 B4
−−−−−−→
1, C
(
)
(
)
→
(
0
0
B3 B4
0
0
0 B4
(
0 0
→
)
0
0 0
0
0 0 Es
5¿øCUC A /G. du1C–p, ⁄–
B –UYzIO/, UC A /G.
B =
B1 B2
B3 B4
ø⁄y†.
0
0
0 B4
6
1.2. UkfmCX
CHAPTER1. :n
1.2 UkfmCX
˜ F kˆ¡ı(’X·Œ), @o F m V U§kı
fmCX. ·3fm V1, V2,··· ,Vm ƒ V ⊆ V1 ∪ V2 ∪ ··· ∪ Vm.
y†: y{: V ⊆ V1 ∪ V2 ∪ ··· ∪ Vm · V ⁄kfmCX¥(?
m − 1 fmUCX V ). @oØ?1 6 i 6 m,
Vi $ V1 ∪ V2 ∪ ··· ∪ Vi¡1 ∪ Vi+1 ∪ ··· ∪ Vm.
˜K m ·4gæ. lz Vi kgC“k”. V1 k α
V2 k β, e¡y5| λα + β ¥kˆ¡ıÆu V1, V2,··· ,Vm ¥?
. ø·ˇ λα + β oÆu V1, g i > 2 XJ λ1 λ2 ƒ
λ1α + β, λ2α + βÆ3 Vi ¥, @o (λ1α + β) − (λ2α + β) = (λ1 − λ2)α Æ3
Vi ¥, α ‰´gæ! ⁄–z Vi ¥ık/X λα + β. ˜kˆ¡ı
, l8{ λα + β | λ ∈ F }¥kˆ¡ı, ⁄–7kˆ¡ıU
V1,··· ,Vm CX.
V ·k/, k{’y†: ε1, ε2,··· ,εn · V |˜,
αi = ε1 + iε2 + ··· + in¡1εn
d1“£ˆ¡S α1, α2,··· , αn,··· ¥? n ⁄ V |
˜, kıfmU„¥kı, lkˆ¡ı αi UCX.
e¡ø(4›.
XJm V 5C A Aı“4ı“, @o3
v ∈ V ƒ v, Av, ··· , An¡1v · V |˜.
y†: f (x) · A Aı“, m(x) · A 4ı“. (, V ¥?
v 4z"ı“ mv(x) A 4ı“ m(x). · m(x) kkı
ˇf, ⁄– v H V , mv(x) kkıU m1(x), m2(x),··· ,mk(x).
˜Vi = {v ∈ V
m, ⁄–7k, Vi ƒ V = Vi, @ok m(x) = mi(x), = f (x) = mi(x). ·‘
3 V ¥ v ƒ v 4z"ı“· A Aı“. @o n
v, Av, ··· , An¡1v 7,·5ˆ’£o⁄, l§⁄ V |˜.
3'¥ø v ¡“”.
flfl mi(A)v = 0}, @o V Æu V1,··· ,Vk ¿, l V1,··· ,Vk U·f
7