<s>
Interaction	B-Application
nets	I-Application
are	O
a	O
graphical	O
model	O
of	O
computation	O
devised	O
by	O
Yves	O
Lafont	O
in	O
1990	O
as	O
a	O
generalisation	O
of	O
the	O
proof	O
structures	O
of	O
linear	O
logic	O
.	O
</s>
<s>
Interaction	B-Application
nets	I-Application
are	O
an	O
inherently	O
distributed	O
model	O
of	O
computation	O
in	O
the	O
sense	O
that	O
computations	O
can	O
take	O
place	O
simultaneously	O
in	O
many	O
parts	O
of	O
an	O
interaction	O
net	O
,	O
and	O
no	O
synchronisation	O
is	O
needed	O
.	O
</s>
<s>
Thus	O
interaction	B-Application
nets	I-Application
provide	O
a	O
natural	O
language	O
for	O
massive	O
parallelism	O
.	O
</s>
<s>
Interaction	B-Application
nets	I-Application
are	O
at	O
the	O
heart	O
of	O
many	O
implementations	O
of	O
the	O
lambda	B-Language
calculus	I-Language
,	O
such	O
as	O
efficient	O
closed	O
reduction	O
and	O
optimal	O
,	O
in	O
Lévy	O
's	O
sense	O
,	O
Lambdascope	O
.	O
</s>
<s>
Graphically	O
,	O
the	O
primitive	O
structures	O
of	O
interaction	B-Application
nets	I-Application
can	O
be	O
represented	O
as	O
follows	O
:	O
</s>
<s>
Textual	O
representation	O
of	O
interaction	B-Application
nets	I-Application
is	O
called	O
the	O
interaction	O
calculus	O
and	O
can	O
be	O
seen	O
as	O
a	O
programming	O
language	O
.	O
</s>
<s>
rewriting	O
defined	O
on	O
interaction	B-Application
nets	I-Application
.	O
</s>
<s>
Generally	O
only	O
deadlock-free	O
interaction	B-Application
nets	I-Application
are	O
considered	O
.	O
</s>
<s>
Interaction	B-Application
nets	I-Application
benefit	O
from	O
the	O
following	O
properties	O
:	O
</s>
<s>
Interaction	B-Application
nets	I-Application
are	O
essentially	O
deterministic	O
and	O
cannot	O
model	O
non-deterministic	O
computations	O
directly	O
.	O
</s>
<s>
In	O
order	O
to	O
express	O
non-deterministic	O
choice	O
,	O
interaction	B-Application
nets	I-Application
need	O
to	O
be	O
extended	O
.	O
</s>
