¤U¤@¶: Polynomials over unique factorization
¤W¤@¶: Unique Factorization Domain
«e¤@¶: Unique Factorization Domain
¹ï©ó¤@Ó unique factorization domain
§ÚÌ¥i¥H¹³³B²z¾ã¼Æªº±¡ªp¨Ó³B²z¤@¨Ç¦³Ãö©ó divisor ªº°ÝÃD. ¤ñ¤è»¡¦b
¤¤n§ä¨ì¨â¤¸¯À a, b ªº greatest common divisor
°£¤F§Q¥ÎÁÓÂà¬Û°£ªk¥ , §ÚÌÁÙ¥i±N a, b °µ½è¦]¼Æ¤À¸Ñ¥H¨D¥X greatest
common divisor.
¹ï©ó¤@¯ëªº unique factorization domain R ¥Ñ©ó R ¤£¤@©w¬O
Euclidean domain, ©Ò¥HµLªk¥ÎÃþ¦üÁÓÂà¬Û°£ªkªº¤èªk¨D greatest common
divisor. µM¦ÓY a, b R, §ÚÌ¥i¥H§Q¥Î unique factorization
domain ªº©Ê½è±N a, b ¤À¸Ñ¦¨
a = u . p1n1 ... prnr, ¤Î b = v . p1m1 ... prnr, |
(8.1) |
¨ä¤¤ u, v ¬O R ¤¤ªº units,
p1,..., pr ¬O R ¤¤¨â¨â¤£
associates ªº irreducible elements, ¦Ó¹ï¥ô·Nªº
i {1,..., r},
ni ©M mi ³£¬O«Dt¦ý¤£¦P®É¬° 0 ªº¾ã¼Æ. ³o¸Ì§ÚÌ¥i¥Hn¨D
p1,..., pr ³£¥X²¦b a, b ªº½è¦]¼Æªº¤À¸Ñ¤¤¥Dn¬O§ÚÌ®e³ ni
©Î mi ¬° 0, ©Ò¥HY pi | a ¦ý
pib §ÚÌ¥O mi = 0.
¤Ï¤§Y pj | b ¦ý
pja, «h¥O nj = 0. ¦]¦¹Y¥O
d = p1t1 ... prtr,
¨ä¤¤
ti = min{ni, mi},
§ÚÌ¥i¥HÃÒ©ú d ¬O a, b ªº greatest common divisor.
Proposition 8.4.1
°²³]
R ¬O¤@Ó unique factorization domain ¥B
a1,...,
an ¬O
R ¤¤ªº«D 0 ¤¸¯À, «h
a1,...,
an ªº greatest common divisor
¦s¦b.
µý ©ú.
§Q¥Î Lemma
8.1.6 §ÚÌ¥unÃÒ©ú
R ¤¤¥ô·N¨âÓ«D 0 ¤¸¯À
a
©M
b ªº greatest common divisor ¦s¦b§Y¥i.
º¥ý§Ú̱N a, b ªº¤À¸Ñ¼g¦¨¦¡¤l (8.1) ªº§Î¦¡, ¥B¥O
d = p1t1 ... prtr,
¨ä¤¤
ti = min{
ni,
mi}.
§ÚÌnÃÒ©ú
d ¬O
a,
b ªº greatest common divisor.
º¥ý¥Ñ
timi ¥H¤Î
tini,
i = 1,..., r,
«Ü®e©ö±oª¾ d | a ¥B d | b. ¦]¦¹ª¾ d ¬O a, b ªº common
divisor. ²Y c ¬O a, b ªº¤@Ó common divisor, °²³] p ¬O¤@Ó
irreducible element ¥B p | c, «h¥Ñ p | a ¥B p | b ª¾ p
¤@©w©M
p1,..., pr ¤¤¬Y¤@Ó pi associates. ³o§i¶D§Ú̦b c
ªº¤À¸Ñ¤¤¤£¥i¯à¥X²©M
p1,..., pr ¤£ associates ªº irreducible
divisor, ¤]´N¬O»¡§Ṳ́]¥i±N c ¤À¸Ñ¦¨
c = w . p1s1 ... prsr,
¨ä¤¤
w ¬O unit ¥B
si
¬O«Dt¾ã¼Æ. ²¦pªG¦³Ó
i ²Å¦X
si >
ni, ¬°¤F¤è«K´N°²³]
s1 >
n1
§a! §Q¥Î
p1s1 |
c ¥H¤Î
c |
a ª¾
p1s1 |
a.
´«¨¥¤§
p1s1 - n1 | p2n2 ... prnr.
¥Ñ
s1 -
n11 ±o
p1 | p2n2 ... prnr.
µM¦Ó
p1 ¬O prime, ³oªí¥Ü
p1 ©M
p2,...,
pr ¤¤¬YÓ
pi
associates. ³o©M·íªì°²³]
p1,...,
pr ¨â¨â¤£ associates ¬Û¥Ù¬Þ,
¬G±o
sini,
i = 1,...,
r. ¦P²z
simi,
i = 1,...,
r. ¬G±oª¾¹ï©Ò¦³ªº
i = 1,...,
r ¬Ò¦³
simin{
ni,
mi} =
ti. ¤]´N¬O»¡
c |
d. ¬Gª¾
d ¬O
a,
b
ªº greatest common divisor.
¦b«e±´X¸`¤¤nÃÒ©ú¤@Ó integral domain ¬O¤@Ó unique factorization
domain, §Ú̳£¥hÃÒ©ú³oÓ integral domain ¤¤ªº irreducible elements
©M prime elements ¬O¤@¼Ëªº. ¨Æ¹ê¤W, ¦b unique factorization domain
¤¤ irreducible element ©M prime element Á`¬O¬Û¦Pªº.
Proposition 8.4.2
Y
R ¬O¤@Ó unique factorization domain, «h
R ¤¤ªº irreducible
elements ©M prime elements ¬O¬Û¦Pªº.
µý ©ú.
§Ṳ́wª¾¦b¤@Ó integral domain ¤¤ prime element ·|¬O irreducible
element (Lemma
8.1.8). ©Ò¥H§ÚÌ¥unÃÒ©ú irreducible element
¤]·|¬O prime element.
°²³] p R ¬O¤@Ó irreducible element ¥B
p | a . b, ¨ä¤¤
a, b R. ¥Ñ°²³]ª¾¦s¦b h R º¡¨¬
a . b = h . p.
º¥ý§Ú̱N a, b ¥Î¦¡¤l (8.1) ªº§Î¦¡¤À¸Ñ, ¦]¦¹¦³
a . b = (u . v) . p1n1 + m1 ... prnr + mr.
§Q¥Î
R ¬O unique factorization
domain, ¥Ñ
a . b ªº¤À¸Ñª¾
p ¤@©w©M
p1,...,
pr ¤¤¬Y¤@Ó
pi associates. µM¦Ó
ni ©M
mi ¤£¦P®É¬° 0, ¤]´N¬O»¡
ni 0 ©Î
mi 0. Y
ni 0, «hª¾
p |
a, ¦ÓY
mi 0
«h¦³
p |
b. ¬G±oÃÒ
p ¬O prime element.
¤U¤@¶: Polynomials over unique factorization
¤W¤@¶: Unique Factorization Domain
«e¤@¶: Unique Factorization Domain
Administrator
2005-06-18