<s>
In	O
the	O
theory	O
of	O
complex	O
systems	O
,	O
a	O
function	B-Application
tree	I-Application
is	O
a	O
diagram	O
showing	O
the	O
dependencies	O
between	O
the	O
functions	O
of	O
a	O
system	O
.	O
</s>
<s>
When	O
used	O
in	O
computer	B-General_Concept
programming	I-General_Concept
,	O
a	O
function	B-Application
tree	I-Application
visualizes	O
which	O
function	O
calls	O
another	O
.	O
</s>
