<s>
HYPO	O
is	O
a	O
computer	B-Application
program	I-Application
that	O
models	O
reasoning	O
with	O
cases	O
and	O
hypotheticals	O
in	O
the	O
legal	O
domain	O
.	O
</s>
<s>
HYPO	O
's	O
design	O
represents	O
a	O
hybrid	B-Device
generalization/comparative	O
evaluation	O
method	O
appropriate	O
for	O
a	O
domain	O
with	O
a	O
weak	O
analytical	O
theory	O
and	O
applies	O
to	O
tasks	O
that	O
rarely	O
involve	O
just	O
one	O
right	O
answer	O
.	O
</s>
<s>
Thus	O
,	O
HYPO	O
did	O
not	O
involve	O
the	O
analysis	O
of	O
a	O
Statute	O
,	O
as	O
required	O
by	O
the	O
PROLOG	B-Language
program	B-Application
.	O
</s>
<s>
HYPO	O
was	O
a	O
successful	O
example	O
of	O
a	O
general	O
category	O
of	O
legal	B-Application
expert	I-Application
systems	I-Application
(	O
LESs	O
)	O
,	O
it	O
applied	O
artificial	B-Application
intelligence	I-Application
(	O
A.I.	B-Application
)	O
</s>
<s>
HYPO	O
use	O
heuristics	B-Algorithm
such	O
as	O
making	O
a	O
case	O
weaker	O
or	O
stronger	O
,	O
making	O
a	O
case	O
extreme	O
,	O
enabling	O
a	O
"	O
near-miss	O
"	O
,	O
disabling	O
a	O
"	O
near-hit	O
"	O
to	O
generate	O
hypotheticals	O
in	O
the	O
context	O
of	O
an	O
argument	O
by	O
using	O
the	O
dimensions	O
mechanism	O
.	O
</s>
<s>
What	O
differentiated	O
this	O
expert	B-Application
system	I-Application
from	O
others	O
was	O
its	O
facility	O
not	O
only	O
to	O
return	O
a	O
primary	O
to	O
best-case	O
response	O
but	O
to	O
return	O
near-best-fit	O
responses	O
as	O
well	O
.	O
</s>
<s>
Plaintiff	O
,	O
defendant	O
,	O
secret	O
knowledge	O
,	O
employer/employee	O
data	O
)	O
.Ashley	O
’	O
s	O
HYPO	O
system	O
used	O
a	O
database	O
of	O
thirty	O
cases	O
in	O
the	O
area	O
indexed	B-Data_Structure
by	O
thirteen	O
dimensions	O
.	O
</s>
<s>
a	O
mechanism	O
to	O
allow	O
retrieval	B-Library
from	O
the	O
CKB	O
,	O
in	O
order	O
to	O
represent	O
legal	O
cases	O
.	O
</s>
<s>
With	O
its	O
use	O
of	O
dimension-based	O
heuristics	B-Algorithm
,	O
the	O
HYPO-generator	O
does	O
a	O
heuristic	B-Algorithm
search	O
of	O
the	O
space	O
of	O
all	O
possible	O
cases	O
.	O
</s>
<s>
Legal	B-Application
expert	I-Application
systems	I-Application
are	O
specifically	O
designed	O
to	O
teach	O
an	O
area	O
of	O
law	O
and	O
are	O
useful	O
for	O
pedagogical	O
purposes	O
.	O
</s>
<s>
Thus	O
,	O
CATO	O
(	O
Aleven	O
1997	O
)	O
was	O
a	O
research	O
project	O
to	O
device	O
and	O
test	O
an	O
intelligent	O
,	O
case-based	O
tutorial	O
program	B-Application
for	O
teaching	O
law	O
students	O
how	O
to	O
argue	O
with	O
cases	O
implementing	O
the	O
HYPO	O
program	B-Application
.	O
</s>
<s>
What	O
makes	O
this	O
tutoring	O
system	O
stand	O
out	O
is	O
the	O
additional	O
levels	O
of	O
abstraction	B-Application
involved	O
in	O
its	O
results	O
.	O
</s>
