<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
a	O
linear	B-Application
graph	I-Application
grammar	I-Application
(	O
also	O
a	O
connection	O
graph	O
reduction	O
system	O
or	O
a	O
port	O
graph	B-Application
grammar	I-Application
)	O
is	O
a	O
class	O
of	O
graph	B-Application
grammar	I-Application
on	O
which	O
nodes	O
have	O
a	O
number	O
of	O
ports	O
connected	O
together	O
by	O
edges	O
and	O
edges	O
connect	O
exactly	O
two	O
ports	O
together	O
.	O
</s>
<s>
Interaction	O
nets	O
are	O
a	O
special	O
subclass	O
of	O
linear	B-Application
graph	I-Application
grammars	I-Application
in	O
which	O
rewriting	O
is	O
confluent	O
.	O
</s>
<s>
Bawden	O
introduces	O
linear	O
graphs	O
in	O
the	O
context	O
of	O
a	O
compiler	O
for	O
a	O
fragment	O
of	O
the	O
Scheme	B-Language
programming	I-Language
language	I-Language
.	O
</s>
