isEmpty
cons
x
xs
false
isEmpty
nil
true
isZero
0
true
isZero
s
x
false
head
cons
x
xs
x
tail
cons
x
xs
xs
tail
nil
nil
p
s
s
x
s
p
s
x
p
s
0
0
p
0
0
inc
s
x
s
inc
x
inc
0
s
0
sumList
xs
y
if
isEmpty
xs
isZero
head
xs
y
tail
xs
cons
p
head
xs
tail
xs
inc
y
if
true
b
y
xs
ys
x
y
if
false
true
y
xs
ys
x
sumList
xs
y
if
false
false
y
xs
ys
x
sumList
ys
x
sum
xs
sumList
xs
0
isEmpty
1
cons
2
false
0
nil
0
true
0
isZero
1
0
0
s
1
head
1
tail
1
p
1
inc
1
sumList
2
if
6
sum
1
INNERMOST
./TRS/secret06/aprove/sumList.trs