Certification Problem
Input (TPDB SRS_Standard/Waldmann_07_size12/size-12-alpha-3-num-59)
The rewrite relation of the following TRS is considered.
a(x1) |
→ |
x1 |
(1) |
a(a(x1)) |
→ |
a(b(a(c(a(x1))))) |
(2) |
c(b(x1)) |
→ |
a(c(x1)) |
(3) |
Property / Task
Prove or disprove termination.Answer / Result
Yes.Proof (by AProVE @ termCOMP 2023)
1 Closure Under Flat Contexts
Using the flat contexts
{a(☐), b(☐), c(☐)}
We obtain the transformed TRS
a(a(x1)) |
→ |
a(b(a(c(a(x1))))) |
(2) |
a(a(x1)) |
→ |
a(x1) |
(4) |
b(a(x1)) |
→ |
b(x1) |
(5) |
c(a(x1)) |
→ |
c(x1) |
(6) |
a(c(b(x1))) |
→ |
a(a(c(x1))) |
(7) |
b(c(b(x1))) |
→ |
b(a(c(x1))) |
(8) |
c(c(b(x1))) |
→ |
c(a(c(x1))) |
(9) |
1.1 Semantic Labeling
Root-labeling is applied.
We obtain the labeled TRS
aa(aa(x1)) |
→ |
ab(ba(ac(ca(aa(x1))))) |
(10) |
aa(ab(x1)) |
→ |
ab(ba(ac(ca(ab(x1))))) |
(11) |
aa(ac(x1)) |
→ |
ab(ba(ac(ca(ac(x1))))) |
(12) |
aa(aa(x1)) |
→ |
aa(x1) |
(13) |
aa(ab(x1)) |
→ |
ab(x1) |
(14) |
aa(ac(x1)) |
→ |
ac(x1) |
(15) |
ba(aa(x1)) |
→ |
ba(x1) |
(16) |
ba(ab(x1)) |
→ |
bb(x1) |
(17) |
ba(ac(x1)) |
→ |
bc(x1) |
(18) |
ca(aa(x1)) |
→ |
ca(x1) |
(19) |
ca(ab(x1)) |
→ |
cb(x1) |
(20) |
ca(ac(x1)) |
→ |
cc(x1) |
(21) |
ac(cb(ba(x1))) |
→ |
aa(ac(ca(x1))) |
(22) |
ac(cb(bb(x1))) |
→ |
aa(ac(cb(x1))) |
(23) |
ac(cb(bc(x1))) |
→ |
aa(ac(cc(x1))) |
(24) |
bc(cb(ba(x1))) |
→ |
ba(ac(ca(x1))) |
(25) |
bc(cb(bb(x1))) |
→ |
ba(ac(cb(x1))) |
(26) |
bc(cb(bc(x1))) |
→ |
ba(ac(cc(x1))) |
(27) |
cc(cb(ba(x1))) |
→ |
ca(ac(ca(x1))) |
(28) |
cc(cb(bb(x1))) |
→ |
ca(ac(cb(x1))) |
(29) |
cc(cb(bc(x1))) |
→ |
ca(ac(cc(x1))) |
(30) |
1.1.1 Rule Removal
Using the
linear polynomial interpretation over the naturals
[aa(x1)] |
= |
1 · x1 + 1 |
[ab(x1)] |
= |
1 · x1 + 1 |
[ba(x1)] |
= |
1 · x1
|
[ac(x1)] |
= |
1 · x1
|
[ca(x1)] |
= |
1 · x1
|
[bb(x1)] |
= |
1 · x1 + 1 |
[bc(x1)] |
= |
1 · x1
|
[cb(x1)] |
= |
1 · x1 + 1 |
[cc(x1)] |
= |
1 · x1
|
all of the following rules can be deleted.
aa(aa(x1)) |
→ |
aa(x1) |
(13) |
aa(ab(x1)) |
→ |
ab(x1) |
(14) |
aa(ac(x1)) |
→ |
ac(x1) |
(15) |
ba(aa(x1)) |
→ |
ba(x1) |
(16) |
ca(aa(x1)) |
→ |
ca(x1) |
(19) |
bc(cb(ba(x1))) |
→ |
ba(ac(ca(x1))) |
(25) |
bc(cb(bb(x1))) |
→ |
ba(ac(cb(x1))) |
(26) |
bc(cb(bc(x1))) |
→ |
ba(ac(cc(x1))) |
(27) |
cc(cb(ba(x1))) |
→ |
ca(ac(ca(x1))) |
(28) |
cc(cb(bb(x1))) |
→ |
ca(ac(cb(x1))) |
(29) |
cc(cb(bc(x1))) |
→ |
ca(ac(cc(x1))) |
(30) |
1.1.1.1 Dependency Pair Transformation
The following set of initial dependency pairs has been identified.
aa#(aa(x1)) |
→ |
ba#(ac(ca(aa(x1)))) |
(31) |
aa#(aa(x1)) |
→ |
ac#(ca(aa(x1))) |
(32) |
aa#(aa(x1)) |
→ |
ca#(aa(x1)) |
(33) |
aa#(ab(x1)) |
→ |
ba#(ac(ca(ab(x1)))) |
(34) |
aa#(ab(x1)) |
→ |
ac#(ca(ab(x1))) |
(35) |
aa#(ab(x1)) |
→ |
ca#(ab(x1)) |
(36) |
aa#(ac(x1)) |
→ |
ba#(ac(ca(ac(x1)))) |
(37) |
aa#(ac(x1)) |
→ |
ac#(ca(ac(x1))) |
(38) |
aa#(ac(x1)) |
→ |
ca#(ac(x1)) |
(39) |
ac#(cb(ba(x1))) |
→ |
aa#(ac(ca(x1))) |
(40) |
ac#(cb(ba(x1))) |
→ |
ac#(ca(x1)) |
(41) |
ac#(cb(ba(x1))) |
→ |
ca#(x1) |
(42) |
ac#(cb(bb(x1))) |
→ |
aa#(ac(cb(x1))) |
(43) |
ac#(cb(bb(x1))) |
→ |
ac#(cb(x1)) |
(44) |
ac#(cb(bc(x1))) |
→ |
aa#(ac(cc(x1))) |
(45) |
ac#(cb(bc(x1))) |
→ |
ac#(cc(x1)) |
(46) |
1.1.1.1.1 Dependency Graph Processor
The dependency pairs are split into 1
component.