<s>
is	O
an	O
experimental	O
proof	O
assistant	O
under	O
development	O
at	O
the	O
Computer	B-General_Concept
Science	I-General_Concept
Department	O
of	O
the	O
University	O
of	O
Bologna	O
.	O
</s>
<s>
It	O
is	O
a	O
tool	O
aiding	O
the	O
development	O
of	O
formal	O
proofs	O
by	O
man-machine	O
collaboration	O
,	O
providing	O
a	O
programming	O
environment	O
where	O
formal	B-Application
specifications	I-Application
,	O
executable	O
algorithms	O
and	O
automatically	O
verifiable	O
correctness	O
certificates	O
naturally	O
coexist	O
.	O
</s>
<s>
Matita	B-Application
is	O
based	O
on	O
a	O
dependent	O
type	O
system	O
known	O
as	O
the	O
Calculus	O
of	O
(	O
Co	O
)	O
Inductive	O
Constructions	O
(	O
a	O
derivative	O
of	O
Calculus	B-Application
of	I-Application
Constructions	I-Application
)	O
,	O
and	O
is	O
compatible	O
,	O
to	O
some	O
extent	O
,	O
with	O
Coq	B-Application
.	O
</s>
<s>
The	O
word	O
"	O
matita	B-Application
"	O
means	O
"	O
pencil	O
"	O
in	O
Italian	O
(	O
a	O
simple	O
and	O
widespread	O
editing	O
tool	O
)	O
.	O
</s>
<s>
Matita	B-Application
adopts	O
a	O
tactic-based	O
editing	O
mode	O
;	O
(	O
XML-encoded	O
)	O
proof	O
objects	O
are	O
produced	O
for	O
storage	O
and	O
exchange	O
.	O
</s>
<s>
Existential	O
variables	O
are	O
native	O
in	O
Matita	B-Application
,	O
allowing	O
a	O
simpler	O
management	O
of	O
dependent	O
goals	O
.	O
</s>
<s>
Matita	B-Application
implements	O
a	O
bidirectional	O
type	O
inference	O
algorithm	O
exploiting	O
both	O
inferred	O
and	O
expected	O
types	O
.	O
</s>
<s>
that	O
helps	O
in	O
synthesizing	O
unifiers	B-Algorithm
in	O
particular	O
situations	O
specified	O
by	O
the	O
user	O
.	O
</s>
<s>
based	O
on	O
a	O
dialog	O
between	O
the	O
parser	B-Language
and	O
the	O
typechecker	O
.	O
</s>
<s>
focused	O
on	O
the	O
development	O
of	O
a	O
formally	O
verified	O
,	O
complexity	O
preserving	O
compiler	O
from	O
a	O
large	O
subset	O
of	O
C	O
to	O
the	O
assembler	O
of	O
a	O
MCS-51	B-Architecture
microprocessor	O
.	O
</s>
<s>
The	O
Matita	B-Application
tutorial	O
provides	O
a	O
pragmatic	O
introduction	O
to	O
the	O
main	O
functionalities	O
of	O
the	O
Matita	B-Application
interactive	O
theorem	O
prover	O
,	O
offering	O
a	O
guided	O
tour	O
through	O
a	O
set	O
of	O
non-trivial	O
examples	O
in	O
the	O
field	O
of	O
software	B-Application
specification	I-Application
and	O
verification	O
.	O
</s>
