<s>
The	O
Provenance	B-Language
Markup	I-Language
Language	I-Language
(	O
abbreviated	O
PML	O
;	O
originally	O
called	O
Proof	B-Language
Markup	I-Language
Language	I-Language
)	O
is	O
an	O
interlingua	O
for	O
representing	O
and	O
sharing	O
knowledge	O
about	O
how	O
information	O
published	O
on	O
the	O
Web	O
was	O
asserted	O
from	O
information	O
sources	O
and/or	O
derived	O
from	O
Web	O
information	O
by	O
intelligent	B-General_Concept
agents	I-General_Concept
.	O
</s>
<s>
The	O
language	O
was	O
initially	O
developed	O
in	O
support	O
of	O
DARPA	B-Language
Agent	I-Language
Markup	I-Language
Language	I-Language
with	O
a	O
goal	O
of	O
explaining	O
how	O
automated	B-Application
theorem	I-Application
provers	I-Application
(	O
ATP	O
)	O
derive	O
conclusions	O
from	O
a	O
set	O
of	O
axioms	B-Algorithm
.	O
</s>
<s>
Information	O
can	O
also	O
play	O
the	O
role	O
of	O
axiom	B-Algorithm
that	O
is	O
basically	O
a	O
conclusion	O
with	O
no	O
antecedents	O
.	O
</s>
<s>
The	O
original	O
set	O
of	O
requirements	O
were	O
relaxed	O
to	O
include	O
the	O
following	O
:	O
information	O
originally	O
represented	O
as	O
logical	O
sentences	O
in	O
the	O
Knowledge	B-Language
Interchange	I-Language
Format	I-Language
were	O
allowed	O
to	O
be	O
information	O
written	O
in	O
any	O
language	O
including	O
the	O
English	O
language	O
;	O
and	O
inference	O
rules	O
originally	O
defined	O
as	O
patterns	O
over	O
antecedents	O
and	O
conclusions	O
of	O
inference	O
steps	O
were	O
allowed	O
to	O
be	O
underspecified	O
as	O
long	O
as	O
they	O
were	O
identified	O
and	O
named	O
.	O
</s>
<s>
Enhancements	O
were	O
also	O
required	O
to	O
further	O
understand	O
motivation	O
behind	O
the	O
need	O
of	O
automated	B-Application
theorem	I-Application
provers	I-Application
to	O
derive	O
conclusions	O
:	O
new	O
capabilities	O
were	O
added	O
to	O
annotate	O
how	O
information	O
playing	O
the	O
role	O
of	O
axioms	B-Algorithm
were	O
attributes	O
as	O
assertions	O
from	O
information	O
sources	O
;	O
and	O
the	O
notion	O
of	O
questions	O
and	O
answers	O
were	O
introduced	O
to	O
the	O
language	O
to	O
explain	O
to	O
a	O
third-party	O
agent	O
why	O
an	O
automated	B-Application
theorem	I-Application
prover	I-Application
was	O
used	O
to	O
prove	O
a	O
theorem	O
(	O
i.e.	O
,	O
an	O
answer	O
)	O
from	O
a	O
given	O
set	O
of	O
axioms	B-Algorithm
.	O
</s>
