Left Termination of the query pattern
reverse_in_2(a, g)
w.r.t. the given Prolog program could not be shown:
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
Clauses:
app(.(X, Xs), Ys, .(X, Zs)) :- app(Xs, Ys, Zs).
app([], Ys, Ys).
reverse(.(X, Xs), Ys) :- ','(reverse(Xs, Zs), app(Zs, .(X, []), Ys)).
reverse([], []).
Queries:
reverse(a,g).
We use the technique of [30].Transforming Prolog into the following Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x3)
U1(x1, x2, x3, x4, x5) = U1(x5)
Infinitary Constructor Rewriting Termination of PiTRS implies Termination of Prolog
↳ Prolog
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PrologToPiTRSProof
Pi-finite rewrite system:
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x3)
U1(x1, x2, x3, x4, x5) = U1(x5)
Using Dependency Pairs [1,30] we result in the following initial DP problem:
Pi DP problem:
The TRS P consists of the following rules:
REVERSE_IN(.(X, Xs), Ys) → U21(X, Xs, Ys, reverse_in(Xs, Zs))
REVERSE_IN(.(X, Xs), Ys) → REVERSE_IN(Xs, Zs)
U21(X, Xs, Ys, reverse_out(Xs, Zs)) → U31(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
U21(X, Xs, Ys, reverse_out(Xs, Zs)) → APP_IN(Zs, .(X, []), Ys)
APP_IN(.(X, Xs), Ys, .(X, Zs)) → U11(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
APP_IN(.(X, Xs), Ys, .(X, Zs)) → APP_IN(Xs, Ys, Zs)
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x3)
U1(x1, x2, x3, x4, x5) = U1(x5)
REVERSE_IN(x1, x2) = REVERSE_IN
U31(x1, x2, x3, x4) = U31(x2, x4)
U21(x1, x2, x3, x4) = U21(x4)
U11(x1, x2, x3, x4, x5) = U11(x5)
APP_IN(x1, x2, x3) = APP_IN(x1, x2)
We have to consider all (P,R,Pi)-chains
↳ Prolog
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ PrologToPiTRSProof
Pi DP problem:
The TRS P consists of the following rules:
REVERSE_IN(.(X, Xs), Ys) → U21(X, Xs, Ys, reverse_in(Xs, Zs))
REVERSE_IN(.(X, Xs), Ys) → REVERSE_IN(Xs, Zs)
U21(X, Xs, Ys, reverse_out(Xs, Zs)) → U31(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
U21(X, Xs, Ys, reverse_out(Xs, Zs)) → APP_IN(Zs, .(X, []), Ys)
APP_IN(.(X, Xs), Ys, .(X, Zs)) → U11(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
APP_IN(.(X, Xs), Ys, .(X, Zs)) → APP_IN(Xs, Ys, Zs)
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x3)
U1(x1, x2, x3, x4, x5) = U1(x5)
REVERSE_IN(x1, x2) = REVERSE_IN
U31(x1, x2, x3, x4) = U31(x2, x4)
U21(x1, x2, x3, x4) = U21(x4)
U11(x1, x2, x3, x4, x5) = U11(x5)
APP_IN(x1, x2, x3) = APP_IN(x1, x2)
We have to consider all (P,R,Pi)-chains
The approximation of the Dependency Graph [30] contains 2 SCCs with 4 less nodes.
↳ Prolog
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PrologToPiTRSProof
Pi DP problem:
The TRS P consists of the following rules:
APP_IN(.(X, Xs), Ys, .(X, Zs)) → APP_IN(Xs, Ys, Zs)
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x3)
U1(x1, x2, x3, x4, x5) = U1(x5)
APP_IN(x1, x2, x3) = APP_IN(x1, x2)
We have to consider all (P,R,Pi)-chains
For (infinitary) constructor rewriting [30] we can delete all non-usable rules from R.
↳ Prolog
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PiDPToQDPProof
↳ PiDP
↳ PrologToPiTRSProof
Pi DP problem:
The TRS P consists of the following rules:
APP_IN(.(X, Xs), Ys, .(X, Zs)) → APP_IN(Xs, Ys, Zs)
R is empty.
The argument filtering Pi contains the following mapping:
.(x1, x2) = .(x2)
APP_IN(x1, x2, x3) = APP_IN(x1, x2)
We have to consider all (P,R,Pi)-chains
Transforming (infinitary) constructor rewriting Pi-DP problem [30] into ordinary QDP problem [15] by application of Pi.
↳ Prolog
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PiDPToQDPProof
↳ QDP
↳ QDPSizeChangeProof
↳ PiDP
↳ PrologToPiTRSProof
Q DP problem:
The TRS P consists of the following rules:
APP_IN(.(Xs), Ys) → APP_IN(Xs, Ys)
R is empty.
Q is empty.
We have to consider all (P,Q,R)-chains.
By using the subterm criterion [20] together with the size-change analysis [32] we have proven that there are no infinite chains for this DP problem. From the DPs we obtained the following set of size-change graphs:
- APP_IN(.(Xs), Ys) → APP_IN(Xs, Ys)
The graph contains the following edges 1 > 1, 2 >= 2
↳ Prolog
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ PiDP
↳ UsableRulesProof
↳ PrologToPiTRSProof
Pi DP problem:
The TRS P consists of the following rules:
REVERSE_IN(.(X, Xs), Ys) → REVERSE_IN(Xs, Zs)
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x3)
U1(x1, x2, x3, x4, x5) = U1(x5)
REVERSE_IN(x1, x2) = REVERSE_IN
We have to consider all (P,R,Pi)-chains
For (infinitary) constructor rewriting [30] we can delete all non-usable rules from R.
↳ Prolog
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PiDPToQDPProof
↳ PrologToPiTRSProof
Pi DP problem:
The TRS P consists of the following rules:
REVERSE_IN(.(X, Xs), Ys) → REVERSE_IN(Xs, Zs)
R is empty.
The argument filtering Pi contains the following mapping:
.(x1, x2) = .(x2)
REVERSE_IN(x1, x2) = REVERSE_IN
We have to consider all (P,R,Pi)-chains
Transforming (infinitary) constructor rewriting Pi-DP problem [30] into ordinary QDP problem [15] by application of Pi.
↳ Prolog
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PiDPToQDPProof
↳ QDP
↳ NonTerminationProof
↳ PrologToPiTRSProof
Q DP problem:
The TRS P consists of the following rules:
REVERSE_IN → REVERSE_IN
R is empty.
Q is empty.
We have to consider all (P,Q,R)-chains.
We used the non-termination processor [17] to show that the DP problem is infinite.
Found a loop by semiunifying a rule from P directly.
The TRS P consists of the following rules:
REVERSE_IN → REVERSE_IN
The TRS R consists of the following rules:none
s = REVERSE_IN evaluates to t =REVERSE_IN
Thus s starts an infinite chain as s semiunifies with t with the following substitutions:
- Semiunifier: [ ]
- Matcher: [ ]
Rewriting sequence
The DP semiunifies directly so there is only one rewrite step from REVERSE_IN to REVERSE_IN.
We use the technique of [30].Transforming Prolog into the following Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x1, x2, x3)
U1(x1, x2, x3, x4, x5) = U1(x2, x3, x5)
Infinitary Constructor Rewriting Termination of PiTRS implies Termination of Prolog
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
Pi-finite rewrite system:
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x1, x2, x3)
U1(x1, x2, x3, x4, x5) = U1(x2, x3, x5)
Using Dependency Pairs [1,30] we result in the following initial DP problem:
Pi DP problem:
The TRS P consists of the following rules:
REVERSE_IN(.(X, Xs), Ys) → U21(X, Xs, Ys, reverse_in(Xs, Zs))
REVERSE_IN(.(X, Xs), Ys) → REVERSE_IN(Xs, Zs)
U21(X, Xs, Ys, reverse_out(Xs, Zs)) → U31(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
U21(X, Xs, Ys, reverse_out(Xs, Zs)) → APP_IN(Zs, .(X, []), Ys)
APP_IN(.(X, Xs), Ys, .(X, Zs)) → U11(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
APP_IN(.(X, Xs), Ys, .(X, Zs)) → APP_IN(Xs, Ys, Zs)
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x1, x2, x3)
U1(x1, x2, x3, x4, x5) = U1(x2, x3, x5)
REVERSE_IN(x1, x2) = REVERSE_IN
U31(x1, x2, x3, x4) = U31(x2, x4)
U21(x1, x2, x3, x4) = U21(x4)
U11(x1, x2, x3, x4, x5) = U11(x2, x3, x5)
APP_IN(x1, x2, x3) = APP_IN(x1, x2)
We have to consider all (P,R,Pi)-chains
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
Pi DP problem:
The TRS P consists of the following rules:
REVERSE_IN(.(X, Xs), Ys) → U21(X, Xs, Ys, reverse_in(Xs, Zs))
REVERSE_IN(.(X, Xs), Ys) → REVERSE_IN(Xs, Zs)
U21(X, Xs, Ys, reverse_out(Xs, Zs)) → U31(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
U21(X, Xs, Ys, reverse_out(Xs, Zs)) → APP_IN(Zs, .(X, []), Ys)
APP_IN(.(X, Xs), Ys, .(X, Zs)) → U11(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
APP_IN(.(X, Xs), Ys, .(X, Zs)) → APP_IN(Xs, Ys, Zs)
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x1, x2, x3)
U1(x1, x2, x3, x4, x5) = U1(x2, x3, x5)
REVERSE_IN(x1, x2) = REVERSE_IN
U31(x1, x2, x3, x4) = U31(x2, x4)
U21(x1, x2, x3, x4) = U21(x4)
U11(x1, x2, x3, x4, x5) = U11(x2, x3, x5)
APP_IN(x1, x2, x3) = APP_IN(x1, x2)
We have to consider all (P,R,Pi)-chains
The approximation of the Dependency Graph [30] contains 2 SCCs with 4 less nodes.
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ UsableRulesProof
↳ PiDP
Pi DP problem:
The TRS P consists of the following rules:
APP_IN(.(X, Xs), Ys, .(X, Zs)) → APP_IN(Xs, Ys, Zs)
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x1, x2, x3)
U1(x1, x2, x3, x4, x5) = U1(x2, x3, x5)
APP_IN(x1, x2, x3) = APP_IN(x1, x2)
We have to consider all (P,R,Pi)-chains
For (infinitary) constructor rewriting [30] we can delete all non-usable rules from R.
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PiDPToQDPProof
↳ PiDP
Pi DP problem:
The TRS P consists of the following rules:
APP_IN(.(X, Xs), Ys, .(X, Zs)) → APP_IN(Xs, Ys, Zs)
R is empty.
The argument filtering Pi contains the following mapping:
.(x1, x2) = .(x2)
APP_IN(x1, x2, x3) = APP_IN(x1, x2)
We have to consider all (P,R,Pi)-chains
Transforming (infinitary) constructor rewriting Pi-DP problem [30] into ordinary QDP problem [15] by application of Pi.
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PiDPToQDPProof
↳ QDP
↳ QDPSizeChangeProof
↳ PiDP
Q DP problem:
The TRS P consists of the following rules:
APP_IN(.(Xs), Ys) → APP_IN(Xs, Ys)
R is empty.
Q is empty.
We have to consider all (P,Q,R)-chains.
By using the subterm criterion [20] together with the size-change analysis [32] we have proven that there are no infinite chains for this DP problem. From the DPs we obtained the following set of size-change graphs:
- APP_IN(.(Xs), Ys) → APP_IN(Xs, Ys)
The graph contains the following edges 1 > 1, 2 >= 2
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ PiDP
↳ UsableRulesProof
Pi DP problem:
The TRS P consists of the following rules:
REVERSE_IN(.(X, Xs), Ys) → REVERSE_IN(Xs, Zs)
The TRS R consists of the following rules:
reverse_in([], []) → reverse_out([], [])
reverse_in(.(X, Xs), Ys) → U2(X, Xs, Ys, reverse_in(Xs, Zs))
U2(X, Xs, Ys, reverse_out(Xs, Zs)) → U3(X, Xs, Ys, app_in(Zs, .(X, []), Ys))
app_in([], Ys, Ys) → app_out([], Ys, Ys)
app_in(.(X, Xs), Ys, .(X, Zs)) → U1(X, Xs, Ys, Zs, app_in(Xs, Ys, Zs))
U1(X, Xs, Ys, Zs, app_out(Xs, Ys, Zs)) → app_out(.(X, Xs), Ys, .(X, Zs))
U3(X, Xs, Ys, app_out(Zs, .(X, []), Ys)) → reverse_out(.(X, Xs), Ys)
The argument filtering Pi contains the following mapping:
reverse_in(x1, x2) = reverse_in
[] = []
reverse_out(x1, x2) = reverse_out(x1, x2)
.(x1, x2) = .(x2)
U2(x1, x2, x3, x4) = U2(x4)
U3(x1, x2, x3, x4) = U3(x2, x4)
app_in(x1, x2, x3) = app_in(x1, x2)
app_out(x1, x2, x3) = app_out(x1, x2, x3)
U1(x1, x2, x3, x4, x5) = U1(x2, x3, x5)
REVERSE_IN(x1, x2) = REVERSE_IN
We have to consider all (P,R,Pi)-chains
For (infinitary) constructor rewriting [30] we can delete all non-usable rules from R.
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PiDPToQDPProof
Pi DP problem:
The TRS P consists of the following rules:
REVERSE_IN(.(X, Xs), Ys) → REVERSE_IN(Xs, Zs)
R is empty.
The argument filtering Pi contains the following mapping:
.(x1, x2) = .(x2)
REVERSE_IN(x1, x2) = REVERSE_IN
We have to consider all (P,R,Pi)-chains
Transforming (infinitary) constructor rewriting Pi-DP problem [30] into ordinary QDP problem [15] by application of Pi.
↳ Prolog
↳ PrologToPiTRSProof
↳ PrologToPiTRSProof
↳ PiTRS
↳ DependencyPairsProof
↳ PiDP
↳ DependencyGraphProof
↳ AND
↳ PiDP
↳ PiDP
↳ UsableRulesProof
↳ PiDP
↳ PiDPToQDPProof
↳ QDP
↳ NonTerminationProof
Q DP problem:
The TRS P consists of the following rules:
REVERSE_IN → REVERSE_IN
R is empty.
Q is empty.
We have to consider all (P,Q,R)-chains.
We used the non-termination processor [17] to show that the DP problem is infinite.
Found a loop by semiunifying a rule from P directly.
The TRS P consists of the following rules:
REVERSE_IN → REVERSE_IN
The TRS R consists of the following rules:none
s = REVERSE_IN evaluates to t =REVERSE_IN
Thus s starts an infinite chain as s semiunifies with t with the following substitutions:
- Semiunifier: [ ]
- Matcher: [ ]
Rewriting sequence
The DP semiunifies directly so there is only one rewrite step from REVERSE_IN to REVERSE_IN.