<s>
In	O
the	O
field	O
of	O
mathematics	O
called	O
combinatorial	O
optimization	O
,	O
the	O
method	O
of	O
symmetry-breaking	B-Application
constraints	I-Application
can	O
be	O
used	O
to	O
take	O
advantage	O
of	O
symmetries	O
in	O
many	O
constraint	B-Application
satisfaction	I-Application
and	O
optimization	O
problems	O
,	O
by	O
adding	O
constraints	O
that	O
eliminate	O
symmetries	O
and	O
reduce	O
the	O
search	O
space	O
size	O
.	O
</s>
<s>
The	O
solution	O
time	O
of	O
a	O
combinatorial	O
problem	O
can	O
be	O
reduced	O
by	O
adding	O
new	O
constraints	O
,	O
referred	O
as	O
symmetry	B-Application
breaking	I-Application
constraints	I-Application
,	O
such	O
that	O
some	O
of	O
the	O
symmetric	O
solutions	O
are	O
eliminated	O
from	O
the	O
search	O
space	O
while	O
preserving	O
the	O
existence	O
of	O
at	O
least	O
one	O
solution	O
.	O
</s>
<s>
For	O
example	O
,	O
certain	O
vehicles	O
in	O
the	O
vehicle	B-Algorithm
routing	I-Algorithm
problem	I-Algorithm
might	O
be	O
identical	O
.	O
</s>
