<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
an	O
action	B-Application
language	I-Application
is	O
a	O
language	O
for	O
specifying	O
state	B-Application
transition	I-Application
systems	I-Application
,	O
and	O
is	O
commonly	O
used	O
to	O
create	O
formal	O
models	O
of	O
the	O
effects	O
of	O
actions	O
on	O
the	O
world	O
.	O
</s>
<s>
Action	B-Application
languages	I-Application
are	O
commonly	O
used	O
in	O
the	B-Application
artificial	I-Application
intelligence	I-Application
and	O
robotics	O
domains	O
,	O
where	O
they	O
describe	O
how	O
actions	O
affect	O
the	O
states	O
of	O
systems	O
over	O
time	O
,	O
and	O
may	O
be	O
used	O
for	O
automated	B-Application
planning	I-Application
.	O
</s>
<s>
Action	B-Application
languages	I-Application
fall	O
into	O
two	O
classes	O
:	O
action	B-Language
description	I-Language
languages	I-Language
and	O
action	O
query	O
languages	O
.	O
</s>
<s>
Examples	O
of	O
the	O
former	O
include	O
STRIPS	B-Application
,	O
PDDL	B-Application
,	O
Language	O
A	O
(	O
a	O
generalization	O
of	O
STRIPS	B-Application
;	O
the	O
propositional	O
part	O
of	O
Pednault	O
's	O
ADL	O
)	O
,	O
Language	O
B	O
(	O
an	O
extension	O
of	O
A	O
adding	O
indirect	O
effects	O
,	O
distinguishing	O
static	O
and	O
dynamic	O
laws	O
)	O
and	O
Language	O
C	O
(	O
which	O
adds	O
indirect	O
effects	O
also	O
,	O
and	O
does	O
not	O
assume	O
that	O
every	O
fluent	O
is	O
automatically	O
"	O
inertial	O
"	O
)	O
.	O
</s>
<s>
There	O
are	O
also	O
the	O
Action	O
Query	O
Languages	O
P	O
,	O
Q	O
and	O
R	O
.	O
Several	O
different	O
algorithms	O
exist	O
for	O
converting	O
action	B-Application
languages	I-Application
,	O
and	O
in	O
particular	O
,	O
action	B-Application
language	I-Application
C	O
,	O
to	O
answer	B-Application
set	I-Application
programs	I-Application
.	O
</s>
<s>
Since	O
modern	O
answer-set	O
solvers	O
make	O
use	O
of	O
boolean	B-Algorithm
SAT	I-Algorithm
algorithms	O
to	O
very	O
rapidly	O
ascertain	O
satisfiability	O
,	O
this	O
implies	O
that	O
action	B-Application
languages	I-Application
can	O
also	O
enjoy	O
the	O
progress	O
being	O
made	O
in	O
the	O
domain	O
of	O
boolean	B-Algorithm
SAT	I-Algorithm
solving	O
.	O
</s>
<s>
All	O
action	B-Application
languages	I-Application
supplement	O
the	O
definition	O
of	O
a	O
state	B-Application
transition	I-Application
system	I-Application
with	O
a	O
set	O
F	O
of	O
fluents	O
,	O
a	O
set	O
V	O
of	O
values	O
that	O
fluents	O
may	O
take	O
,	O
and	O
a	O
function	O
mapping	O
S	O
×	O
F	O
to	O
V	O
,	O
where	O
S	O
is	O
the	O
set	O
of	O
states	O
of	O
a	O
state	B-Application
transition	I-Application
system	I-Application
.	O
</s>
