<s>
Writer	B-General_Concept
invariant	I-General_Concept
,	O
also	O
called	O
authorial	O
invariant	O
or	O
author	O
's	O
invariant	O
,	O
is	O
a	O
property	O
of	O
a	O
text	O
which	O
is	O
invariant	O
of	O
its	O
author	O
,	O
that	O
is	O
,	O
it	O
will	O
be	O
similar	O
in	O
all	O
texts	O
of	O
a	O
given	O
author	O
and	O
different	O
in	O
texts	O
of	O
different	O
authors	O
.	O
</s>
<s>
Writer	B-General_Concept
invariant	I-General_Concept
is	O
also	O
an	O
author	O
's	O
pattern	O
of	O
writing	O
a	O
letter	O
in	O
handwritten	O
text	B-Application
recognition	I-Application
.	O
</s>
<s>
While	O
it	O
is	O
generally	O
recognised	O
that	O
writer	B-General_Concept
invariants	I-General_Concept
exist	O
,	O
it	O
is	O
not	O
agreed	O
what	O
properties	O
of	O
a	O
text	O
should	O
be	O
used	O
.	O
</s>
