rityj.ie iso)iaaron.chan/tna/2020/matsui...2 x subsets ¢ 2 £ 0-csh
TRANSCRIPT
§0. Introduction
keywordse.ci initial dimensiono f a specialization closed subset o f SpecR
い 、 geometry
o n w i d e subcategorieso f ModR l muniform subcategorieso f D lModR)
• m e s he v e n t subse ts of giが"84 t h eOne. representationtheory
. . . i d e a l theory.
A I
Study t h e relation among them using"small support".
I I D IMs aR )Fo r M E ModR . t h e smwsutp.meo fM i s
supplies:={pE SpecRITyj.IE?iso)I たが詬
char-うたき嵓
が 籅{pl E(名)くのE''(M))
N o t e : A s M e suppM e SuppM:=(PESpeeR lMpが 1F o r I N C SpeeR , s e t
s u ppin(IN)は {MEModR I Supp(M)<W|
s u pp i (IN) は {XED(MoaR ) I supp(X) C I N |
F o r INCS_pecR.piny.TT?JTiYd0neefunaa
しguppies) L e s ModR
I f I N i s specialization closed.
HiNw(M))E Hi(M):= 1でた1M)し た(M) =に E M I Supp(Ra)C I N l )
D IF o r a specialization closed subset I N C SpecP ,
ed(IN):= i nf f i s o I Hui(M)=0 fo r "ME MoaRfi t h eJ i d d i m e n s A IN.
i f I N i s c l o s e d ,fed(IN) =(the
e shomologicaldimension o f t h e scheme SpecR、川|+ 1
② Known results.
晋前がでんささらNeman
1992)
⑦ -c l osed Servehisc a t . of m a
Rt"がでる釘ががとても ど →
{smashinga tsubse ts o f Spea R |← of D lModR )
u
も 1 - )supp(A)
!
U.net
supp(M) く - 1 がs up i l lN ) f r o n t I N 1 - ) Suppbtw,
化がIModR : S e e
"
で も i s c losed u n d e r submodules,
quotient modules, extensions.
' K LD(ModR):sina.dertk.is
"
-close d t h i ck
G も い D lM o dR ) has a right adj.which preserves direct s u m s .
' I N C SpecR : s p e c i a l i t y (sp.cl.)とでHpcq c SpecR . p e I N ⇒ 9 E I N .
Easy_Fc.eeFo r a sp.cl. subset I N C SpeeR ,
cd(IN) E O や IN' i s sp.cl.
Ihr(Krause 20081ヨが、
|
#
-closed wide
s u bc a r . of M o dR |
!
f"""""
"
|<
!
fはH)-closed
t h i ck |of SpecR s u bc a t . o f D I MO dR )
Here,・ K < M o dR こwidens間 I t i s c l osed under kernels, a kennels,
extensions.
- )-(CD(ModR ) i H i d e " X E t t H I X ) E t
$
)"
' I N a SpecR i a h e d t " I I I ' w i t h だいら AssごくIN,
ざごーごーごこ e x . s e
wi th ごこimj.. A ssご く が
正 (Angereri H i igee,Marks, Staidk , Takahashi, Vitor ia 2018)
For a sp .c l subset I N a SpeeR ,
ed(IN) E l くニ> パン cohe ren t
W e w a n t t o consider higher c ohomological d im cd lIN ) S h .
N h n wide s ubc a t . n uniform s u beat . , me s he v e n t subset
P I
SO Introduction
8 1 Subcategories o f M o dR ID(ModR)5 2 . Subsets o f SpeeR53. M a i n Result
§ 1 . Subcategories of M o dRID(MFR)⑨ Subcategories of M o dR
t s u bc a t . t c M o d R i s
• dosedunderm_ifio-M-x-X-n.mx". が EH"
ニ) M Et.foseundan.am/_if,,
x n - ) - _ - X 、 一 x 。 _ M t o , X i E K
⇒ M E A
•w w i d e i f H i s closed u n d e r n Ke r,musk .ext .
F E E T u n d e r 0-Kernel や c l o s e d u n d e r s u bm o d .
I kernels
c losed u n d e r 0 - c s k や c l o s e d u n d e r quot.mad
I nparticular,'
e sKerner
0 - w i d e = Serve
I - w i d e = w i d e
(2) 0 -w i d e で 1 - w i d e の - . - ⇒ a w ideい I I
Serve wide
I I I . I
L e t F : M o aR - M o dR b e a left e x a c t functor with が F = 0 .Then
{ M E M o dR I R'た(M)2 0 1
i s a w ide
Similar r e s u l t holds for t h e l e f t derived functor o fa night e x funa 、
心 に ) 2 .E 1 . 2(l) L e t I N C SpeeR : sp e l . w i t h
cd(INFE n .
T h e n
(MG M o d R I Hi(M)= o for i s が 、 n I - spil lNYi s w wider. i
ed(IN) E n 一-) supp(IN') i n _w i d e .
12) L a T E M o dR . i o T E h.
T h e n
f M f M o dR l E x eE(M,T) s o Ii s m w i d e
13) L e t T G M o d R . p dT S h.
Then
1ME M o d R I Extが(T. M) 2 0 1
1 M E M o d R I T a E ( T. M ) 2 0 |a r e m w i d e
⑨ Subcategories o f D lM o dR )
DefA T th ick subc a t . A C D ( R ) i s n i n e
& Let X E K . i t Z s . い
て HI(X) = 0 for i t j G ( i n . i th)
. が G た f o r j e f i n . i tn ]
Thenで(X)
,
がイが(x,E A -
"
學a n d H i s の一closed, then
Z i s m uniform
← > L e n X t K . i t Z s e
' HI ( X ) z o fo r i t j G ( i . u . i tn )
T h e n H「(X)E H
This u s e s t h e resu l ts by N e em a n , Nakamura- Yoshino ?
・ (Neeman) t s s u pfb(IN) for Z I NC SpecR• (Nakamura-Yoshino) supp(X) C I N ⇒ x I ヨ Y i n D IM o eR )
S . t . suppY''C I N
l Hi,(2)
"
-c l ose d O - un i form = smashing
- ' ' T I - uniform 2 H . closed
- い ー か uniform = H の . c losed th ick s u bcat .
(3) 0-uniform = ) I_uniform ⇒ 2-uniform=) . . . → p-uniform.
I I I . 3 I n EIN)L e t F i ModR - ) M o dR be a left e x a c t functor withRT=0.T h e "
f x a D e a R , I RFIX) 2 0 1i s w uniform
E 1 . 4
い、 L e t I N C SpecR isp.cl. with Cd(IN) S hな "
f x ED (Moa R ) I Rた( x ) E o f =supi b(w')
i s n_uniform.
i . ed(IN) E n で suppI '(IN') i m uniform.
(2) Le t T E M o dR a t . i d T E h .
T h e n
( x I RHom(X.T)が1i s w uniform
D L e t T G M o dR s . t . pdT s n .
Then
l X I RH omr ( T X ) t o 1
1 × 1 T I n X E o fa n e w uniform .
§ 2 Subsets o f SpeeR
I IA s u b s e t I N C SpecR i s
m o sFo r a n e x . s e e
A s I i c I N
e.際𡵅
!
萩市となった
w t h I i e s
Ass(C) C I N .
O r a s he v e n t = sp.cl.
a s _ cohe ren t 2 はsubsets
(2) 0 - c s h ⇒ 1-csh → - _ - で は 一 u h .
❤
How t o f ind m e s he v e n subsets
暭
"
f o r u s .い) H s u b s e t . A SpecR i s に u h(2) H sp.cl. s u b s e t . I N o f SpeeR , CdlIN) で
(3) d i mR E n
R eTh is resul t u s e s a bigCohen.Macaulay module M .
w h o s e e x i s t e n c e i s f o n e of the homological m ieames".proved by Andre' (20/6).
T o prove いる(3), u s e t h e mining. resale of M .
12-22 (Groin vanishing then)I N C SpeeR
Hp E I N , h i p s n ⇒ INC : m e s h .
1R i t d i m ring , I N C SpeeR
'
I N i 0 - o h や I N い sp.cl.ObsI I )
s H subse ts a r e I r i s h by
P r o p 2 . I -R・ たいか 、
IN※generalization c losed l i e . I N ' i spell
'
I N こ O - c s h や I N ? sp.d' I N : t b h # m G I N I N z SpeeR
" " R. m
( E) :Prop2.2 、 _ _ _. h tで
(ニ) . ' H a r t s h o r n e Lichte nbaum. .vanishing theo rem
- H (gen. el.)subsets a r e 2 - c l o s e d
by Prop2.I
§ 3 . M a i n Result.
S u -...::※..嫗王に!.iem e s h . sp.cl. cohe re n t . . .
MaintenanceF o r M E INしたり、 ヨが. が(か.E)-closed
awide|
!
Incoheren t
subs!!にPassed )subcat.of M o dR o f SpeeR m uniforms u be a t .
A D(MoaR)い
た t e n t appDt) K e n t Isuppi M く ~ 1 I N l e t s suppj (W)
Here, K C Mo dR i E t c h e s越 はME K . E''(M) E K .か)
弁。
C I M C ' ' ' C I N .I T I t
C . c a c . e c jI T I T
U . C U、 C - _ - C U c s
F-M o dR i かclosed (1-)wide 一-) も i E_closed.
兵も= 0 Gabriel 11962) N e emanに992)
|
"
-
closed Servesubc a t . f
!
ftp.d.subseesf
#
fsmashing sube a tA M o dR & SpecR o f D(ModR) |
Krause(2008)y(2) n = I
|
"
-closed wide sub
cat.ffff
Coherentsubsets}
=|B.H)- closed thick fo f SpecR s u bc a t of D lModR )A M o dR
Takahashi(20°9)Neeman11993(3) n z
of
"
,E t
closed b _ w i d e s u bCat.|
!
I Pe eReb の一 c l o s e d thick subea t . |A Mo dR A D lM o dR )
I T M - N a m Takahashi- Tr i -Yen)F o r a sp.c l s u b s e t I N C SpecR ,
e d (IN) E n 一一〉 supply(パ) i n w ide
a n d " # ' holds i f n E l o r n s d i nR i .
I 3 . 3F o r a sp.cl. subset I N e SpeeR ,
ed(IN, E h 一-) INC i n c o h e r e n t
a n d "が holds i t gg o r m
Angenew Hi igel a d ." "
'器any2 E n s d i mR-2, ヨcounter example to"← ".