<s>
This	O
equivalence	O
is	O
commonly	O
used	O
in	O
logic	B-Language
programming	I-Language
,	O
where	O
clauses	O
are	O
usually	O
written	O
as	O
an	O
implication	O
in	O
this	O
form	O
.	O
</s>
<s>
If	O
n	O
=	O
1	O
and	O
m	O
=	O
0	O
,	O
the	O
clause	O
is	O
called	O
a	O
(	O
Prolog	B-Language
)	O
fact	O
.	O
</s>
<s>
If	O
n	O
=	O
1	O
and	O
m	O
>	O
0	O
,	O
the	O
clause	O
is	O
called	O
a	O
(	O
Prolog	B-Language
)	O
rule	O
.	O
</s>
<s>
If	O
n	O
=	O
0	O
and	O
m	O
>	O
0	O
,	O
the	O
clause	O
is	O
called	O
a	O
(	O
Prolog	B-Language
)	O
query	O
.	O
</s>
<s>
If	O
n	O
>	O
1	O
,	O
the	O
clause	O
is	O
no	O
longer	O
Horn	B-Application
.	O
</s>
