<s>
A	O
duration	B-Algorithm
row	I-Algorithm
or	O
duration	B-Algorithm
series	I-Algorithm
is	O
an	O
ordering	O
of	O
a	O
set	O
of	O
durations	O
,	O
in	O
analogy	O
with	O
the	O
tone	O
row	O
or	O
twelve-tone	O
set	O
.	O
</s>
<s>
Messiaen	O
had	O
,	O
however	O
,	O
previously	O
used	O
this	O
chromatic	O
duration	B-Algorithm
series	I-Algorithm
as	O
an	O
ordered	O
set	O
in	O
the	O
opening	O
episode	O
of	O
"	O
Turangalîla	O
2	O
"	O
,	O
a	O
movement	O
from	O
the	O
Turangalîla-Symphonie	O
(	O
1946	O
–	O
48	O
)	O
.	O
</s>
<s>
Babbitt	O
's	O
Composition	O
for	O
Four	O
Instruments	O
(	O
1948	O
)	O
uses	O
a	O
four-element	O
duration	B-Algorithm
row	I-Algorithm
:	O
1	O
4	O
3	O
2	O
(	O
the	O
second	O
note	O
is	O
four	O
times	O
the	O
duration	O
of	O
the	O
first	O
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
Babbitt	O
's	O
Composition	O
for	O
Twelve	O
Instruments	O
(	O
1948	O
)	O
uses	O
a	O
twelve-element	O
duration	B-Algorithm
set	I-Algorithm
to	O
serialize	O
the	O
rhythms	O
as	O
well	O
as	O
the	O
pitches	O
.	O
</s>
<s>
He	O
would	O
later	O
employ	O
an	O
approach	O
based	O
on	O
time-points	B-Algorithm
.	O
</s>
<s>
Babbitt	O
's	O
use	O
of	O
rhythm	O
in	O
the	O
latter	O
piece	O
was	O
criticized	O
by	O
Peter	O
Westergaard	O
in	O
Perspectives	O
of	O
New	O
Music	O
:	O
"	O
can	O
we	O
be	O
expected	O
to	O
hear	O
a	O
family	O
resemblance	O
between	O
a	O
dotted	O
half	O
note	O
followed	O
by	O
a	O
sixteenth	O
note	O
(	O
the	O
opening	O
'	O
interval	O
 '	O
of	O
duration	B-Algorithm
set	I-Algorithm
P0	O
)	O
and	O
an	O
eighth	O
note	O
followed	O
by	O
a	O
dotted	O
eighth	O
note	O
(	O
the	O
opening	O
'	O
interval	O
 '	O
of	O
duration	B-Algorithm
set	I-Algorithm
P2	O
)	O
?	O
"	O
</s>
<s>
A	O
duration	B-Algorithm
set	I-Algorithm
based	O
on	O
the	O
harmonic	O
series	O
would	O
introduce	O
irrational	O
values	O
.	O
</s>
