<s>
In	O
numerical	B-General_Concept
analysis	I-General_Concept
,	O
mortar	B-Algorithm
methods	I-Algorithm
are	O
discretization	B-Algorithm
methods	I-Algorithm
for	O
partial	O
differential	O
equations	O
,	O
which	O
use	O
separate	O
finite	B-Application
element	I-Application
discretization	B-Algorithm
on	O
nonoverlapping	O
subdomains	O
.	O
</s>
<s>
The	O
meshes	B-Algorithm
on	O
the	O
subdomains	O
do	O
not	O
match	O
on	O
the	O
interface	O
,	O
and	O
the	O
equality	O
of	O
the	O
solution	O
is	O
enforced	O
by	O
Lagrange	O
multipliers	O
,	O
judiciously	O
chosen	O
to	O
preserve	O
the	O
accuracy	O
of	O
the	O
solution	O
.	O
</s>
<s>
Mortar	O
discretizations	B-Algorithm
lend	O
themselves	O
naturally	O
to	O
the	O
solution	O
by	O
iterative	O
domain	B-Algorithm
decomposition	I-Algorithm
methods	I-Algorithm
such	O
as	O
FETI	B-Algorithm
and	O
balancing	B-Algorithm
domain	I-Algorithm
decomposition	I-Algorithm
In	O
the	O
engineering	O
practice	O
in	O
the	O
finite	B-Application
element	I-Application
method	I-Application
,	O
continuity	O
of	O
solutions	O
between	O
non-matching	O
subdomains	O
is	O
implemented	O
by	O
multiple-point	O
constraints	O
.	O
</s>
