119: exemples d`actions de groupes sur les espaces de

A
2 3 k
A
GLp(A)×GLq(A)Mp,q(A)ϕ(P, Q, M)7→
P MQ−1
∃(P, Q)B=P AQ−1
E F B0B0
0
E B1B0
1F P Q
A f B0B1
f Q−1AP
r Ir
r0
Z
1−1 1 2
D d1|d2. . . |dn
did0
i
di

(1,1, . . . 1)
SL
SL ×SL
GLp(A)Mp(A)ϕ: (P, M)7→ P MP −1
∃P B =P AP −1
p= 2
M2(R)
n63
E
K

A
v
n
n
dimK[u] = n↔dimC(u) = n↔deg(µu) = n↔µu=χu↔C(A) = K[u]↔u
⇔u
u K[u] = C(u)u
Dim(C(u)) = Pn
1(2s−2i+ 1)deg(Pi) = Pi,h min(dim(Pi), dim(Pj)) Pi
K[u] = C(C(u))
P−1=tP A
A