<s>
Perfect	B-Application
Developer	I-Application
(	O
PD	O
)	O
is	O
a	O
tool	O
for	O
developing	O
computer	B-Application
programs	I-Application
in	O
a	O
rigorous	O
manner	O
.	O
</s>
<s>
Even	O
though	O
the	O
tool	O
is	O
founded	O
on	O
formal	B-Architecture
methods	I-Architecture
,	O
the	O
suppliers	O
claim	O
that	O
advanced	O
mathematical	O
knowledge	O
is	O
not	O
a	O
prerequisite	O
.	O
</s>
<s>
PD	O
supports	O
the	O
Verified	O
Design	B-Application
by	I-Application
Contract	I-Application
paradigm	O
,	O
which	O
is	O
an	O
extension	O
of	O
Design	B-Application
by	I-Application
contract	I-Application
.	O
</s>
<s>
In	O
Verified	O
Design	B-Application
by	I-Application
Contract	I-Application
,	O
the	O
contracts	O
are	O
verified	O
by	O
static	O
analysis	O
and	O
automated	O
theorem	O
proving	O
,	O
so	O
that	O
it	O
is	O
certain	O
that	O
they	O
will	O
not	O
fail	O
at	O
runtime	O
.	O
</s>
<s>
The	O
Perfect	O
specification	B-Application
language	I-Application
used	O
has	O
an	O
object-oriented	B-Language
style	O
,	O
producing	O
code	O
in	O
programming	O
languages	O
including	O
Java	B-Language
,	O
C#	B-Application
and	O
C++	B-Language
.	O
</s>
