¤U¤@¶: ¤@¨Ç±`¨£ªº Rings
¤W¤@¶: ¯S®íªº Ideals
«e¤@¶: Prime ideals
¦b
¤¤½è¼Æ¥t¤@Ó«nªº©Ê½è¬O°£¤F 1 ©M¥»¨¥ ¥¦¤£·|¬O¨ä¥L¾ã¼Æªº¿¼Æ.
¥H«á§ÚÌ·|ª¾¹D¦b¾ã¼Æ¤¤©Ò¦³ªº ideal ¬Ò¬O principle ideal. ©Ò¥H¥Î
ideal ªºÆ[ÂI¨Ó¬Ý³oªí¥Ü¤@Ó½è¼Æ©Ò§Î¦¨ªº principle ideal
¤£·|¥]§t©ó¨ä¥Lªº nontrivial proper ideal.
¦]¦¹§Ú̦³¥H¤U¥t¤@Ó±À¼s½è¼Æ©Ê½èªº¯S®í ideal.
Definition 6.5.9
Y R ¬O¤@Ó ring ¥B M ¬O R ¤¤ªº¤@Ó nontrivial proper ideal,
¦pªG M ¤£·|¥]§t©ó R ¤¤¨ä¥Lªº nontrivial proper ideal, «h§Ú̺Ù
M ¬O¤@Ó maximal ideal.
ª`·N, §O³Q ``maximal'' ³oÓ¦rµ¹ÄF¤F. ¦b¼Æ¾Ç¤W«Ü¦h±¡ªp¤U, maximal
¬Oªí¥Ü¨S¦³ªF¦è¤ñ¥¦¤j, ¨Ã¤£ªí¥Ü¥¦¤ñ©Ò¦³ªºªF¦è¤j.
(§Ṳ́£³o¼Ë©w¥Dn¬O¦b«Ü¦h±¡ªp¤U§ÚÌn±´°QªºªF¦è¨Ã¤£¬O well-ordered,
¤]´N¬O¦³®É¨â¼ËªF¦è¬O¤£¯à¤ñ¸ûªº.) ¦]¦¹, Y M ¬O R ªº¤@Ó maximal
ideal ¥B I ¬O R ªº¤@Ó nontrivial proper ideal, ³o¨Ã¤£ªí¥Ü
I M, ¦Ó¥u¬O»¡¦pªG
M I, «h I = M.
±q³oӬݪk¤j®aÀ³¤]¥i¥H¬Ý¥X¦³¥i¯à¦b R ¤¤¦³¤£¥u¤@Ó maximal ideal.
§Æ±æ¤U¤@Ó¨Ò¤l¥i¥HÂç²M³oÓÆ[©À.
Example 6.5.10
¦Ò¼
¤¤
6
³o¤@Ó ideal. §ÚÌ«Ü®e©ö¬Ý¥X¨Ó
6
2
¥B¦]
2
2
¦ý
2
6
,
§Ú̪¾
6
2
. ¦A¥[¤W
2
¬O
ªº¤@Ó
nontrivial proper ideal, ¬Gª¾
6
¤£¬O
ªº maximal ideal.
¤£¹L
2
¬O
ªº maximal ideal. ¦]¬°¦pªG
2
¤£¬O
maximal ideal, «h¨Ì©w¸qª¾¦s¦b¤@Ó
¤¤ªº nontrivial proper
ideal
I º¡¨¬
2
I. ´«¥y»¡¦s¦b¤@¾ã¼Æ
a I ¦ý
a 2
(³oªí¥Ü
a ¬O¤@Ó©_¼Æ). ©Ò¥H¦s¦b¤@¾ã¼Æ
n ¨Ï±o
a = 2
. n + 1. §O§Ñ¤F§ÚÌ°²³]
I ¬O ideal ¥B 2
I, ©Ò¥H
2
. n I. ¦A¥[¤W
a I, ¦]¦¹±o
1 =
a - 2
. n I. ¥Ñ
Lemma
6.2.4 ª¾
I =
, ³o©M§ÚÌ°²³]
I ¬O nontrivial proper
ideal ¬Û¥Ù¬Þ, ¬G±o
2
¬O
ªº maximal ideal. ¤£¹L¥Ñ©ó
3
2
, §Ú̪¾
3
³oÓ ideal ¨Ã¤£¥]§t©ó
2
.
¬Æ¦Ü¹ï¥ô·Nªº
n ,
3
n ³£¤£·|¥]§t©ó
2
. ©Ò¥H
maximal ideal ·|¤ñ©Ò¦³ªº nontrivial proper ideal
³£¤j³o¼Ëªº»¡ªk¨Ã¤£¥¿½T. ¥t¤@¤è±, §ÚÌ¥i¥H¥Î«e±Ãþ¦üªº¤èªk±o¨ì¦b
¤¤¥ô·N¤@Ó½è¼Æ©Ò²£¥Íªº principle ideal ³£¬O maximal ideal,
©Ò¥H
¤¤ªº maximal ideal ¨Ã¤£¥u¤@Ó (¨ä¹ê¦³µL½a¦hÓ).
±µ¤U¨Ó§ÚÌ·Q¥ÎÃþ¦ü Theorem 6.5.7 ªº¤èªk§Q¥Î quotient ring
¨Ó§P§O¤@Ó ideal ¬O§_¬° maximal ideal.
Theorem 6.5.11
Y
R ¬O¤@Ó commutative ring with 1 ¥B
M ¬O
R ªº¤@Ó ideal,
«h
M ¬O
R ªº¤@Ó maximal ideal Y¥B°ßY
R/
M ³oÓ quotient ring
¬O¤@Ó field.
µý ©ú.
º¥ýÆ[¹î¥Ñ°²³]¥iª¾
R/
M ¬O¤@Ó commutative ring with 1, ©Ò¥H
R/
M ¬O¤@Ó field ¬Û·í©ó¥un»¡
R/
M ¤¤¤£µ¥©ó
ªº¤¸¯À³£¬O
unit.
²°²³] M ¬O R ªº maximal ideal. ¥ô¨ú R/M ¤¤¤@¤¸¯À
, §Ú̦³ a R ¥B
a M. ¥Ñ Lemma
6.2.1 ª¾
M +
a = {
m +
r . a |
m M,
r R}
¬O
R
ªº¤@Ó ideal. ¥Ñ©ó
M M +
a ¥B
a M, §Ú̪¾
MM +
a, §Y
M +
a ¬O¤@Ó¤ñ
M ¤jªº ideal. ¦ý¥Ñ
M
¬O maximal ideal ªº°²³]§Ú̪¾
M +
a ¤£¬O
R ªº nontrivial
proper ideal. ´«¥y¸Ü»¡
M +
a =
R. §Q¥Î
1
R =
M +
a,
§Ú̪¾¦s¦b
m M,
r R º¡¨¬
1 =
m +
r . a.
§O§Ñ¤F§Ú̬On°Q½×
R/
M ªº¤¸¯À, ©Ò¥H¥Ñ¤W¦¡¥H¤Î¦b
R/
M ¤¤
=
§Ú̦³
¦]¦¹
¬O
R/
M ªº unit, ¬Gª¾
R/
M ¬O¤@Ó field.
¤Ï¤§Y R/M ¬O¤@Ó field, §ÚÌ·QÃÒ M ¬O R ªº¤@Ó maximal ideal.
¦A¦¸±j½Õ§Ṳ́£¬OnÃÒ©ú¥ô·N R ¤¤ªº nontrivial proper ideal ³£º¡¨¬
I M, ¦Ó¬OnÃÒ©ú¤£¥i¯à
M I. §ÚÌn¥Î¤ÏÃÒªk:
°²³] M ¤£¬O maximal ideal, §Y¦s¦b¤@Ó nontrivial proper ideal I
º¡¨¬
M I. ¥Ñ
M I ¦ý MI ª¾¦s¦b a I
¦ý
a M, ¤]´N¬O»¡¦b R/M ¤¤
. ¦ý R/M
¬O¤@Ó field, ¬G¦s¦b r R ¨Ï±o
³o§i¶D§ÚÌ
1 -
r . a M, ¤]´N¬O»¡
1 =
m +
r . a
¨ä¤¤
m M. ¥Ñ©ó
a I ¥B
I ¬O¤@Ó ideal, §Ú̪¾
r . a I. ¦]¦¹¥Ñ
m M I ±o
1 =
m +
r . a I. Lemma
6.2.4 §i¶D§ÚÌ 1
I ªí¥Ü
I =
R, ¦¹©M
I ¬O nontrivial
proper ideal ¬Û¥Ù¬Þ, ¬Gª¾
M ¬O maximal ideal.
Remark 6.5.12
§ÚÌ¥i¥H§Q¥Î Correspondence ©w²z«Ü§ÖªºÃÒ©ú Theorem
6.5.11.
¦^ÅU¤@¤U Corollary
6.3.7 §i¶D§ÚÌ
R/
M ¤¤ªº ideal
³£¬O¥Ñ¤¶©ó
R ©M
M ¶¡ªº ideal ©Ò§Î¦¨. ¦]¦¹Y
M ¬O maximal
ideal, ªí¥Ü¤¶©ó
R ©M
M ¶¡©Ò¦³ªº ideal ¥u¦³
R ©M
M. ´«¥y¸Ü»¡
R/
M ¤¤¥u¦³
R/
M ©M
M/
M =
³o¨âÓ ideal ¦Ó¨S¦³
nontrivial proper ideal, ©Ò¥H¥Ñ Proposition
6.5.5 ª¾
R/
M
¬O¤@Ó field. ¥t¤@¤è±¦pªG
R/
M ¬O¤@Ó field, ¦P¼Ëªº¥Ñ Proposition
6.5.5 §Ú̪¾
R/
M ¨S¦³ nontrivial proper ideal.
¦]¦¹¥Ñ§Ú̦b Remark
6.3.6 ¤¤´£¨ìªº¤ñ¸û±j(¦³°ß¤@©Ê)ªº
Correspondence ©w²zª¾¨S¦³¨ä¥Lªº ideal ¤¶©ó
R ©M
M ¤§¶¡, ¬G±o
M
¬O maximal ideal.
§Ú̪¾¹D¦b¤@Ó field ¤¤«D 0 ªº¤¸¯À³£¬O unit, µM¦Ó Lemma 5.3.7
§i¶D§Ṳ́@Ó unit µ´¤£·|¬O zero divisor, ©Ò¥H§Ú̪¾¹D¤@Ó field
¨Æ¹ê¤W¬O¤@Ó integral domain. ²Y R/M ¬O¤@Ó field, «h R/M
¬O¤@Ó integral domain. ©Ò¥H¥Ñ Theorem 6.5.7 ©M Theorem
6.5.11 ¥i±o¥H¤U¤§µ²ªG:
Corollary 6.5.13
Y
R ¬O¤@Ó commutative ring with 1, «h
R ¤¤ªº maximal ideal
³£¬O prime ideal.
ª`·N Corollary 6.5.13 ¤Ï¹L¨Ó¨Ã¤£¤@©w¹ï. ¨Ò¦p¦b
¤¤§Ú̪¾
/0 , ¦ý
¬O integral domain «o¤£¬O field,
©Ò¥Hª¾
0 ¬O
ªº prime ideal ¦ý¤£¬O maximal ideal.
¤U¤@¶: ¤@¨Ç±`¨£ªº Rings
¤W¤@¶: ¯S®íªº Ideals
«e¤@¶: Prime ideals
Administrator
2005-06-18