<s>
The	O
weapon	B-Algorithm
target	I-Algorithm
assignment	I-Algorithm
problem	I-Algorithm
(	O
WTA	O
)	O
is	O
a	O
class	O
of	O
combinatorial	O
optimization	O
problems	O
present	O
in	O
the	O
fields	O
of	O
optimization	O
and	O
operations	O
research	O
.	O
</s>
<s>
Notice	O
that	O
as	O
opposed	O
to	O
the	O
classic	O
assignment	B-Algorithm
problem	I-Algorithm
or	O
the	O
generalized	B-Algorithm
assignment	I-Algorithm
problem	I-Algorithm
,	O
more	O
than	O
one	O
agent	O
(	O
i.e.	O
,	O
weapon	O
)	O
can	O
be	O
assigned	O
to	O
each	O
task	O
(	O
i.e.	O
,	O
target	O
)	O
and	O
not	O
all	O
targets	O
are	O
required	O
to	O
have	O
weapons	O
assigned	O
.	O
</s>
<s>
Thus	O
,	O
we	O
see	O
that	O
the	O
WTA	O
allows	O
one	O
to	O
formulate	O
optimal	O
assignment	B-Algorithm
problems	I-Algorithm
wherein	O
tasks	O
require	O
cooperation	O
among	O
agents	O
.	O
</s>
<s>
The	O
weapon	B-Algorithm
target	I-Algorithm
assignment	I-Algorithm
problem	I-Algorithm
is	O
often	O
formulated	O
as	O
the	O
following	O
nonlinear	O
integer	B-Algorithm
programming	I-Algorithm
problem	I-Algorithm
:	O
</s>
<s>
An	O
exact	O
solution	O
can	O
be	O
found	O
using	O
branch	B-Algorithm
and	I-Algorithm
bound	I-Algorithm
techniques	O
which	O
utilize	O
relaxation	O
(	O
approximation	O
)	O
.	O
</s>
<s>
Many	O
heuristic	B-Algorithm
algorithms	I-Algorithm
have	O
been	O
proposed	O
which	O
provide	O
near-optimal	O
solutions	O
in	O
polynomial	O
time	O
.	O
</s>
