<s>
In	O
physics	O
and	O
mathematics	O
,	O
the	O
Hadamard	B-Algorithm
dynamical	I-Algorithm
system	I-Algorithm
(	O
also	O
called	O
Hadamard	B-Algorithm
's	I-Algorithm
billiard	I-Algorithm
or	O
the	O
Hadamard	B-Algorithm
–	I-Algorithm
Gutzwiller	I-Algorithm
model	I-Algorithm
)	O
is	O
a	O
chaotic	O
dynamical	O
system	O
,	O
a	O
type	O
of	O
dynamical	O
billiards	O
.	O
</s>
<s>
The	O
system	O
is	O
particularly	O
important	O
in	O
that	O
in	O
1963	O
,	O
Yakov	O
Sinai	O
,	O
in	O
studying	O
Sinai	O
's	O
billiards	O
as	O
a	O
model	O
of	O
the	O
classical	O
ensemble	O
of	O
a	O
Boltzmann	O
–	O
Gibbs	O
gas	O
,	O
was	O
able	O
to	O
show	O
that	O
the	O
motion	O
of	O
the	O
atoms	O
in	O
the	O
gas	O
follow	O
the	O
trajectories	O
in	O
the	O
Hadamard	B-Algorithm
dynamical	I-Algorithm
system	I-Algorithm
.	O
</s>
