Lemma 6.11
(The entropic BSG theorem)
.
Assuming that:
A
and
B
are
G
-valued random variables
Then
d
[
A
;
B
∥
A
+
B
]
≤
3
I
[
A
:
B
]
+
2
H
[
A
+
B
]
−
H
[
A
]
−
H
[
B
]
.