and
tt
tt
tt
is_nat
0
tt
is_nat
s
x
is_nat
x
is_natlist
nil
tt
is_natlist
cons
x
xs
and
is_nat
x
is_natlist
xs
from
x
fromCond
is_natlist
x
x
fromCond
tt
cons
x
xs
from
cons
s
x
cons
x
xs
2.2
from
x
is_natlist
x
is_natlist
cons
x
xs
is_natlist
xs
is_nat
s
x
is_nat
x
is_natlist
cons
x
xs
is_nat
x
fromCond
tt
cons
x
xs
from
cons
s
x
cons
x
xs
from
x
fromCond
is_natlist
x
x
is_natlist
cons
x
xs
and
is_nat
x
is_natlist
xs
true
from
x
fromCond
is_natlist
x
x
fromCond
tt
cons
x
xs
from
cons
s
x
cons
x
xs
true
Failed!
NaTT
certifiable-1.6