Let
F
\mathcal F
be a family of functions holomorphic on a domain
D
D
in
C
,
\mathbb C,
all of whose zeros are multiple. Let
h
h
be a function meromorphic on
D
,
D,
h
≢
0
,
∞
.
h\not \equiv 0,\infty .
Suppose that for each
f
∈
F
,
f\in \mathcal F,
f
′
(
z
)
≠
h
(
z
)
f’(z)\ne h(z)
for
z
∈
D
.
z\in D.
Then
F
\mathcal F
is a normal family on
D
.
D.