<s>
Transaction	B-Language
Logic	I-Language
is	O
an	O
extension	O
of	O
predicate	O
logic	O
that	O
accounts	O
in	O
a	O
clean	O
and	O
declarative	O
way	O
for	O
the	O
phenomenon	O
of	O
state	O
changes	O
in	O
logic	B-Language
programs	I-Language
and	O
databases	O
.	O
</s>
<s>
Transaction	B-Language
Logic	I-Language
has	O
a	O
Horn	B-Application
clause	I-Application
subset	O
,	O
which	O
has	O
a	O
procedural	O
as	O
well	O
as	O
a	O
declarative	O
semantics	O
.	O
</s>
<s>
In	O
this	O
way	O
,	O
Transaction	B-Language
Logic	I-Language
is	O
able	O
to	O
declaratively	O
capture	O
a	O
number	O
of	O
non-logical	O
phenomena	O
,	O
including	O
procedural	O
knowledge	O
in	O
artificial	B-Application
intelligence	I-Application
,	O
active	O
databases	O
,	O
and	O
methods	O
with	O
side	O
effects	O
in	O
object	B-Application
databases	I-Application
.	O
</s>
<s>
Transaction	B-Language
Logic	I-Language
was	O
originally	O
proposed	O
in	O
by	O
and	O
and	O
later	O
described	O
in	O
more	O
detail	O
in	O
and	O
.	O
</s>
<s>
In	O
later	O
years	O
,	O
Transaction	B-Language
Logic	I-Language
was	O
extended	O
in	O
various	O
ways	O
,	O
including	O
concurrency	B-Operating_System
,	O
defeasible	O
reasoning	O
,	O
partially	O
defined	O
actions	O
,	O
and	O
other	O
features.	O
<	O
ref>H	O
.	O
</s>
<s>
Fodor	O
and	O
M	O
.	O
Kifer	O
(	O
2010	O
)	O
,	O
Tabling	O
for	O
Transaction	B-Language
Logic	I-Language
.	O
</s>
<s>
In	O
2013	O
,	O
the	O
original	O
paper	O
on	O
Transaction	B-Language
Logic	I-Language
has	O
won	O
the	O
20-year	O
Test	O
of	O
Time	O
Award	O
of	O
the	O
Association	O
for	O
Logic	B-Language
Programming	I-Language
as	O
the	O
most	O
influential	O
paper	O
from	O
the	O
proceedings	O
of	O
ICLP	O
1993	O
conference	O
in	O
the	O
preceding	O
20	O
years	O
.	O
</s>
<s>
Here	O
is	O
the	O
logical	O
connective	O
of	O
parallel	O
conjunction	O
of	O
Concurrent	O
Transaction	B-Language
Logic	I-Language
.	O
</s>
<s>
A	O
number	O
of	O
implementations	O
of	O
Transaction	B-Language
Logic	I-Language
exist	O
:	O
</s>
<s>
An	O
implementation	O
of	O
Concurrent	O
Transaction	B-Language
Logic	I-Language
.	O
</s>
<s>
Transaction	B-Language
Logic	I-Language
enhanced	O
with	O
tabling	O
.	O
</s>
<s>
An	O
implementation	O
of	O
Transaction	B-Language
Logic	I-Language
has	O
also	O
been	O
incorporated	O
as	O
part	O
of	O
the	O
Flora-2	B-Language
knowledge	O
representation	O
and	O
reasoning	O
system	O
.	O
</s>
<s>
All	O
these	O
implementations	O
are	O
open	B-License
source	I-License
.	O
</s>
