Termination w.r.t. Q of the given QTRS could not be shown:

0 QTRS
↳1 Overlay + Local Confluence (⇔)
↳2 QTRS
↳3 DependencyPairsProof (⇔)
↳4 QDP
↳5 DependencyGraphProof (⇔)
↳6 AND
  ↳7 QDP
    ↳8 QDPOrderProof (⇔)
    ↳9 QDP
    ↳10 PisEmptyProof (⇔)
    ↳11 TRUE
  ↳12 QDP
    ↳13 QDPOrderProof (⇔)
    ↳14 QDP
    ↳15 PisEmptyProof (⇔)
    ↳16 TRUE
  ↳17 QDP
    ↳18 QDPOrderProof (⇔)
    ↳19 QDP
    ↳20 PisEmptyProof (⇔)
    ↳21 TRUE
  ↳22 QDP

(0) Obligation:

Q restricted rewrite system:
The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

Q is empty.

(1) Overlay + Local Confluence (EQUIVALENT transformation)

The TRS is overlay and locally confluent. By [NOC] we can switch to innermost.

(2) Obligation:

Q restricted rewrite system:
The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

(3) DependencyPairsProof (EQUIVALENT transformation)

Using Dependency Pairs [AG00,LPAR04] we result in the following initial DP problem.

(4) Obligation:

Q DP problem:
The TRS P consists of the following rules:

APPEND(cons(y, ys), x) → APPEND(ys, x)
P(s(s(x))) → P(s(x))
INC(s(x)) → INC(x)
ADDLISTS(xs, ys, zs) → IF(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
ADDLISTS(xs, ys, zs) → ISEMPTY(xs)
ADDLISTS(xs, ys, zs) → ISEMPTY(ys)
ADDLISTS(xs, ys, zs) → ISZERO(head(xs))
ADDLISTS(xs, ys, zs) → HEAD(xs)
ADDLISTS(xs, ys, zs) → TAIL(xs)
ADDLISTS(xs, ys, zs) → TAIL(ys)
ADDLISTS(xs, ys, zs) → P(head(xs))
ADDLISTS(xs, ys, zs) → INC(head(ys))
ADDLISTS(xs, ys, zs) → HEAD(ys)
ADDLISTS(xs, ys, zs) → APPEND(zs, head(ys))
IF(false, false, false, xs, ys, xs2, ys2, zs, zs2) → ADDLISTS(xs2, ys2, zs)
IF(false, false, true, xs, ys, xs2, ys2, zs, zs2) → ADDLISTS(xs, ys, zs2)
ADDLIST(xs, ys) → ADDLISTS(xs, ys, nil)

The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

We have to consider all minimal (P,Q,R)-chains.

(5) DependencyGraphProof (EQUIVALENT transformation)

The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 4 SCCs with 11 less nodes.

(6) Complex Obligation (AND)

(7) Obligation:

Q DP problem:
The TRS P consists of the following rules:

INC(s(x)) → INC(x)

The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

We have to consider all minimal (P,Q,R)-chains.

(8) QDPOrderProof (EQUIVALENT transformation)

We use the reduction pair processor [LPAR04].


The following pairs can be oriented strictly and are deleted.


INC(s(x)) → INC(x)
The remaining pairs can at least be oriented weakly.
Used ordering: Combined order from the following AFS and order.
INC(x1)  =  x1
s(x1)  =  s(x1)

Lexicographic path order with status [LPO].
Quasi-Precedence:
trivial

Status:
s1: [1]


The following usable rules [FROCOS05] were oriented: none

(9) Obligation:

Q DP problem:
P is empty.
The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

We have to consider all minimal (P,Q,R)-chains.

(10) PisEmptyProof (EQUIVALENT transformation)

The TRS P is empty. Hence, there is no (P,Q,R) chain.

(11) TRUE

(12) Obligation:

Q DP problem:
The TRS P consists of the following rules:

P(s(s(x))) → P(s(x))

The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

We have to consider all minimal (P,Q,R)-chains.

(13) QDPOrderProof (EQUIVALENT transformation)

We use the reduction pair processor [LPAR04].


The following pairs can be oriented strictly and are deleted.


P(s(s(x))) → P(s(x))
The remaining pairs can at least be oriented weakly.
Used ordering: Lexicographic path order with status [LPO].
Quasi-Precedence:
[P1, s1]

Status:
P1: [1]
s1: [1]


The following usable rules [FROCOS05] were oriented: none

(14) Obligation:

Q DP problem:
P is empty.
The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

We have to consider all minimal (P,Q,R)-chains.

(15) PisEmptyProof (EQUIVALENT transformation)

The TRS P is empty. Hence, there is no (P,Q,R) chain.

(16) TRUE

(17) Obligation:

Q DP problem:
The TRS P consists of the following rules:

APPEND(cons(y, ys), x) → APPEND(ys, x)

The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

We have to consider all minimal (P,Q,R)-chains.

(18) QDPOrderProof (EQUIVALENT transformation)

We use the reduction pair processor [LPAR04].


The following pairs can be oriented strictly and are deleted.


APPEND(cons(y, ys), x) → APPEND(ys, x)
The remaining pairs can at least be oriented weakly.
Used ordering: Lexicographic path order with status [LPO].
Quasi-Precedence:
[APPEND2, cons2]

Status:
cons2: [2,1]
APPEND2: [2,1]


The following usable rules [FROCOS05] were oriented: none

(19) Obligation:

Q DP problem:
P is empty.
The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

We have to consider all minimal (P,Q,R)-chains.

(20) PisEmptyProof (EQUIVALENT transformation)

The TRS P is empty. Hence, there is no (P,Q,R) chain.

(21) TRUE

(22) Obligation:

Q DP problem:
The TRS P consists of the following rules:

ADDLISTS(xs, ys, zs) → IF(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
IF(false, false, false, xs, ys, xs2, ys2, zs, zs2) → ADDLISTS(xs2, ys2, zs)
IF(false, false, true, xs, ys, xs2, ys2, zs, zs2) → ADDLISTS(xs, ys, zs2)

The TRS R consists of the following rules:

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
append(nil, x) → cons(x, nil)
append(cons(y, ys), x) → cons(y, append(ys, x))
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)
addLists(xs, ys, zs) → if(isEmpty(xs), isEmpty(ys), isZero(head(xs)), tail(xs), tail(ys), cons(p(head(xs)), tail(xs)), cons(inc(head(ys)), tail(ys)), zs, append(zs, head(ys)))
if(true, true, b, xs, ys, xs2, ys2, zs, zs2) → zs
if(true, false, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, true, b, xs, ys, xs2, ys2, zs, zs2) → differentLengthError
if(false, false, false, xs, ys, xs2, ys2, zs, zs2) → addLists(xs2, ys2, zs)
if(false, false, true, xs, ys, xs2, ys2, zs, zs2) → addLists(xs, ys, zs2)
addList(xs, ys) → addLists(xs, ys, nil)

The set Q consists of the following terms:

isEmpty(cons(x0, x1))
isEmpty(nil)
isZero(0)
isZero(s(x0))
head(cons(x0, x1))
tail(cons(x0, x1))
tail(nil)
append(nil, x0)
append(cons(x0, x1), x2)
p(s(s(x0)))
p(s(0))
p(0)
inc(s(x0))
inc(0)
addLists(x0, x1, x2)
if(true, true, x0, x1, x2, x3, x4, x5, x6)
if(true, false, x0, x1, x2, x3, x4, x5, x6)
if(false, true, x0, x1, x2, x3, x4, x5, x6)
if(false, false, false, x0, x1, x2, x3, x4, x5)
if(false, false, true, x0, x1, x2, x3, x4, x5)
addList(x0, x1)

We have to consider all minimal (P,Q,R)-chains.