times
x
y
sum
generate
x
y
generate
x
y
gen
x
y
0
gen
x
y
z
if
ge
z
x
x
y
z
if
true
x
y
z
nil
if
false
x
y
z
cons
y
gen
x
y
s
z
sum
xs
sum2
xs
0
sum2
xs
y
ifsum
isNil
xs
isZero
head
xs
xs
y
ifsum
true
b
xs
y
y
ifsum
false
b
xs
y
ifsum2
b
xs
y
ifsum2
true
xs
y
sum2
tail
xs
y
ifsum2
false
xs
y
sum2
cons
p
head
xs
tail
xs
s
y
isNil
nil
true
isNil
cons
x
xs
false
tail
nil
nil
tail
cons
x
xs
xs
head
cons
x
xs
x
head
nil
error
isZero
0
true
isZero
s
0
false
isZero
s
s
x
isZero
s
x
p
0
s
s
0
p
s
0
0
p
s
s
x
s
p
s
x
ge
x
0
true
ge
0
s
y
false
ge
s
x
s
y
ge
x
y
a
c
a
d
times
2
sum
1
generate
2
gen
3
0
0
if
4
ge
2
true
0
nil
0
false
0
cons
2
s
1
sum2
2
ifsum
4
isNil
1
isZero
1
head
1
ifsum2
3
tail
1
p
1
error
0
a
0
c
0
d
0
FULL
./TRS/secret07/aprove/aprove01.trs