Theorem 8
(Edge-isoperimetric inequality in
Q
n
)
.
Assuming that:
A
⊂
Q
n
let
C
the initial segment of binary on
Q
n
with
|
C
|
=
|
A
|
Then
|
∂
C
|
≤
|
∂
A
|
. In particular: if
|
A
|
=
2
k
then
|
∂
A
|
≥
2
k
(
n
−
k
)
.