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v1= (0,1,1) v2= (1,0,1) v3= (1,1,0)
R3w= (1,1,1) (v1, v2, v3)
v1= (1,1,1) v2= (−1,1,0) v3= (1,0,−1) R3
e1= (1,0,0) e2= (0,1,0) e3= (0,0,1) w= (1,2,−3)
(v1, v2, v3)
R3
R3
t∈R(1,0, t),(1,1, t),(t, 0,1)
R3
v1= (1,−1, i)v2= (−1, i, 1) v3= (i, 1,−1)
C3
v= (1 + i, 1−i, i)
EK
f E K
H E u ∈E\H D =K.u
H
H E dim H= dim E−1
(x, y, z, t)∈R42x−3y+ 2z−4t= 0
(x, y)∈R2−x+ 3y= 0
(x, y, z)∈R3x+y= 0
(x, y, z, t)∈R4x−z+t= 0
R4
v1= (1,2,3,4), v2= (1,1,1,3), v3= (2,1,1,1), v4= (−1,0,−1,2), v5= (2,3,0,1).
F{v1, v2, v3}G{v4, v5}
F G F ∩G F +G
E=R2[X] 2
(1, X + 1, X2+X+ 1) E P =X2
E=Rn[X]{P0, P1, . . . , Pn}deg Pi=i
i= 0,1, . . . , n E
F G E
E=F+G
F∩G={OE}