<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
k-approximation	B-Algorithm
of	I-Algorithm
k-hitting	I-Algorithm
set	I-Algorithm
is	O
an	O
approximation	B-Algorithm
algorithm	I-Algorithm
for	O
weighted	O
hitting	O
set	O
.	O
</s>
<s>
The	O
input	O
is	O
a	O
collection	B-Application
S	O
of	O
subsets	O
of	O
some	O
universe	O
T	O
and	O
a	O
mapping	B-Algorithm
W	O
from	O
T	O
to	O
non-negative	O
numbers	O
called	O
the	O
weights	O
of	O
the	O
elements	O
of	O
T	O
.	O
In	O
k-hitting	O
set	O
the	O
size	O
of	O
the	O
sets	O
in	O
S	O
cannot	O
be	O
larger	O
than	O
k	O
.	O
That	O
is	O
,	O
.	O
</s>
<s>
For	O
an	O
element	O
a	O
in	O
T	O
,	O
let	O
S(a )	O
be	O
the	O
collection	B-Application
of	O
sets	O
from	O
S	O
containing	O
a	O
.	O
</s>
<s>
The	O
intuition	O
is	O
that	O
it	O
is	O
dual	O
to	O
a	O
linear	B-Algorithm
programming	I-Algorithm
algorithm	O
.	O
</s>
