<s>
In	O
statistics	O
,	O
the	O
term	O
linear	B-Algorithm
model	I-Algorithm
is	O
used	O
in	O
different	O
ways	O
according	O
to	O
the	O
context	O
.	O
</s>
<s>
The	O
most	O
common	O
occurrence	O
is	O
in	O
connection	O
with	O
regression	O
models	O
and	O
the	O
term	O
is	O
often	O
taken	O
as	O
synonymous	O
with	O
linear	B-General_Concept
regression	I-General_Concept
model	I-General_Concept
.	O
</s>
<s>
The	O
"	O
linear	O
"	O
part	O
of	O
the	O
designation	O
relates	O
to	O
the	O
appearance	O
of	O
the	O
regression	B-General_Concept
coefficients	I-General_Concept
,	O
in	O
a	O
linear	O
way	O
in	O
the	O
above	O
relationship	O
.	O
</s>
<s>
In	O
this	O
instance	O
the	O
use	O
of	O
the	O
term	O
"	O
linear	B-Algorithm
model	I-Algorithm
"	O
refers	O
to	O
the	O
structure	O
of	O
the	O
above	O
relationship	O
in	O
representing	O
as	O
a	O
linear	O
function	O
of	O
past	O
values	O
of	O
the	O
same	O
time	O
series	O
and	O
of	O
current	O
and	O
past	O
values	O
of	O
the	O
innovations	O
.	O
</s>
<s>
Note	O
that	O
here	O
the	O
"	O
linear	O
"	O
part	O
of	O
the	O
term	O
"	O
linear	B-Algorithm
model	I-Algorithm
"	O
is	O
not	O
referring	O
to	O
the	O
coefficients	O
and	O
,	O
as	O
it	O
would	O
be	O
in	O
the	O
case	O
of	O
a	O
regression	O
model	O
,	O
which	O
looks	O
structurally	O
similar	O
.	O
</s>
<s>
There	O
are	O
some	O
other	O
instances	O
where	O
"	O
nonlinear	O
model	O
"	O
is	O
used	O
to	O
contrast	O
with	O
a	O
linearly	O
structured	O
model	O
,	O
although	O
the	O
term	O
"	O
linear	B-Algorithm
model	I-Algorithm
"	O
is	O
not	O
usually	O
applied	O
.	O
</s>
<s>
One	O
example	O
of	O
this	O
is	O
nonlinear	B-Algorithm
dimensionality	I-Algorithm
reduction	I-Algorithm
.	O
</s>
