<s>
In	O
numerical	B-General_Concept
analysis	I-General_Concept
,	O
a	O
superconvergent	B-Algorithm
or	O
supraconvergent	O
method	O
is	O
one	O
which	O
converges	O
faster	O
than	O
generally	O
expected	O
(	O
superconvergence	B-Algorithm
or	O
supraconvergence	B-Algorithm
)	O
.	O
</s>
<s>
For	O
example	O
,	O
in	O
the	O
Finite	B-Application
Element	I-Application
Method	I-Application
approximation	O
to	O
Poisson	O
's	O
equation	O
in	O
two	O
dimensions	O
,	O
using	O
piecewise	O
linear	O
elements	O
,	O
the	O
average	O
error	O
in	O
the	O
gradient	O
is	O
first	B-Algorithm
order	I-Algorithm
.	O
</s>
<s>
However	O
under	O
certain	O
conditions	O
it	O
's	O
possible	O
to	O
recover	O
the	O
gradient	O
at	O
certain	O
locations	O
within	O
each	O
element	O
to	O
second	B-Algorithm
order	I-Algorithm
.	O
</s>
