Theorem 3.4
(Special case of Changβs Theorem)
.
Assuming that:
A
β
π½
2
n
of density
Ξ±
>
0
Ο
>
0
Then
there exists
H
β€
π½
2
n
^
of dimension
O
(
Ο
β
2
log
β‘
Ξ±
β
1
)
such that
π
H
β
Spec
β‘
Ο
(
π
A
)
.