YES Left Termination proof of ../tpdb/LP/terminweb/old-terminweb/subset.pl
Left Termination of the query pattern subset_in_2(g, g) w.r.t. the given Prolog program could successfully be proven:



↳ Prolog
  ↳ PrologToPiTRSProof

Clauses:

member(X, .(Y, Xs)) :- member(X, Xs).
member(X, .(X, Xs)).
subset(.(X, Xs), Ys) :- ','(member(X, Ys), subset(Xs, Ys)).
subset([], Ys).

Queries:

subset(g,g).

We use the technique of [30]. With regard to the inferred argument filtering the predicates were used in the following modes:
subset_in: (b,b)
member_in: (b,b)
Transforming Prolog into the following Term Rewriting System:
Pi-finite rewrite system:
The TRS R consists of the following rules:

subset_in_gg(.(X, Xs), Ys) → U2_gg(X, Xs, Ys, member_in_gg(X, Ys))
member_in_gg(X, .(Y, Xs)) → U1_gg(X, Y, Xs, member_in_gg(X, Xs))
member_in_gg(X, .(X, Xs)) → member_out_gg(X, .(X, Xs))
U1_gg(X, Y, Xs, member_out_gg(X, Xs)) → member_out_gg(X, .(Y, Xs))
U2_gg(X, Xs, Ys, member_out_gg(X, Ys)) → U3_gg(X, Xs, Ys, subset_in_gg(Xs, Ys))
subset_in_gg([], Ys) → subset_out_gg([], Ys)
U3_gg(X, Xs, Ys, subset_out_gg(Xs, Ys)) → subset_out_gg(.(X, Xs), Ys)

The argument filtering Pi contains the following mapping:
subset_in_gg(x1, x2)  =  subset_in_gg(x1, x2)
.(x1, x2)  =  .(x1, x2)
U2_gg(x1, x2, x3, x4)  =  U2_gg(x2, x3, x4)
member_in_gg(x1, x2)  =  member_in_gg(x1, x2)
U1_gg(x1, x2, x3, x4)  =  U1_gg(x4)
member_out_gg(x1, x2)  =  member_out_gg
U3_gg(x1, x2, x3, x4)  =  U3_gg(x4)
[]  =  []
subset_out_gg(x1, x2)  =  subset_out_gg

Infinitary Constructor Rewriting Termination of PiTRS implies Termination of Prolog



↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof

Pi-finite rewrite system:
The TRS R consists of the following rules:

subset_in_gg(.(X, Xs), Ys) → U2_gg(X, Xs, Ys, member_in_gg(X, Ys))
member_in_gg(X, .(Y, Xs)) → U1_gg(X, Y, Xs, member_in_gg(X, Xs))
member_in_gg(X, .(X, Xs)) → member_out_gg(X, .(X, Xs))
U1_gg(X, Y, Xs, member_out_gg(X, Xs)) → member_out_gg(X, .(Y, Xs))
U2_gg(X, Xs, Ys, member_out_gg(X, Ys)) → U3_gg(X, Xs, Ys, subset_in_gg(Xs, Ys))
subset_in_gg([], Ys) → subset_out_gg([], Ys)
U3_gg(X, Xs, Ys, subset_out_gg(Xs, Ys)) → subset_out_gg(.(X, Xs), Ys)

The argument filtering Pi contains the following mapping:
subset_in_gg(x1, x2)  =  subset_in_gg(x1, x2)
.(x1, x2)  =  .(x1, x2)
U2_gg(x1, x2, x3, x4)  =  U2_gg(x2, x3, x4)
member_in_gg(x1, x2)  =  member_in_gg(x1, x2)
U1_gg(x1, x2, x3, x4)  =  U1_gg(x4)
member_out_gg(x1, x2)  =  member_out_gg
U3_gg(x1, x2, x3, x4)  =  U3_gg(x4)
[]  =  []
subset_out_gg(x1, x2)  =  subset_out_gg


Using Dependency Pairs [1,30] we result in the following initial DP problem:
Pi DP problem:
The TRS P consists of the following rules:

SUBSET_IN_GG(.(X, Xs), Ys) → U2_GG(X, Xs, Ys, member_in_gg(X, Ys))
SUBSET_IN_GG(.(X, Xs), Ys) → MEMBER_IN_GG(X, Ys)
MEMBER_IN_GG(X, .(Y, Xs)) → U1_GG(X, Y, Xs, member_in_gg(X, Xs))
MEMBER_IN_GG(X, .(Y, Xs)) → MEMBER_IN_GG(X, Xs)
U2_GG(X, Xs, Ys, member_out_gg(X, Ys)) → U3_GG(X, Xs, Ys, subset_in_gg(Xs, Ys))
U2_GG(X, Xs, Ys, member_out_gg(X, Ys)) → SUBSET_IN_GG(Xs, Ys)

The TRS R consists of the following rules:

subset_in_gg(.(X, Xs), Ys) → U2_gg(X, Xs, Ys, member_in_gg(X, Ys))
member_in_gg(X, .(Y, Xs)) → U1_gg(X, Y, Xs, member_in_gg(X, Xs))
member_in_gg(X, .(X, Xs)) → member_out_gg(X, .(X, Xs))
U1_gg(X, Y, Xs, member_out_gg(X, Xs)) → member_out_gg(X, .(Y, Xs))
U2_gg(X, Xs, Ys, member_out_gg(X, Ys)) → U3_gg(X, Xs, Ys, subset_in_gg(Xs, Ys))
subset_in_gg([], Ys) → subset_out_gg([], Ys)
U3_gg(X, Xs, Ys, subset_out_gg(Xs, Ys)) → subset_out_gg(.(X, Xs), Ys)

The argument filtering Pi contains the following mapping:
subset_in_gg(x1, x2)  =  subset_in_gg(x1, x2)
.(x1, x2)  =  .(x1, x2)
U2_gg(x1, x2, x3, x4)  =  U2_gg(x2, x3, x4)
member_in_gg(x1, x2)  =  member_in_gg(x1, x2)
U1_gg(x1, x2, x3, x4)  =  U1_gg(x4)
member_out_gg(x1, x2)  =  member_out_gg
U3_gg(x1, x2, x3, x4)  =  U3_gg(x4)
[]  =  []
subset_out_gg(x1, x2)  =  subset_out_gg
U1_GG(x1, x2, x3, x4)  =  U1_GG(x4)
MEMBER_IN_GG(x1, x2)  =  MEMBER_IN_GG(x1, x2)
SUBSET_IN_GG(x1, x2)  =  SUBSET_IN_GG(x1, x2)
U2_GG(x1, x2, x3, x4)  =  U2_GG(x2, x3, x4)
U3_GG(x1, x2, x3, x4)  =  U3_GG(x4)

We have to consider all (P,R,Pi)-chains

↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof

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

SUBSET_IN_GG(.(X, Xs), Ys) → U2_GG(X, Xs, Ys, member_in_gg(X, Ys))
SUBSET_IN_GG(.(X, Xs), Ys) → MEMBER_IN_GG(X, Ys)
MEMBER_IN_GG(X, .(Y, Xs)) → U1_GG(X, Y, Xs, member_in_gg(X, Xs))
MEMBER_IN_GG(X, .(Y, Xs)) → MEMBER_IN_GG(X, Xs)
U2_GG(X, Xs, Ys, member_out_gg(X, Ys)) → U3_GG(X, Xs, Ys, subset_in_gg(Xs, Ys))
U2_GG(X, Xs, Ys, member_out_gg(X, Ys)) → SUBSET_IN_GG(Xs, Ys)

The TRS R consists of the following rules:

subset_in_gg(.(X, Xs), Ys) → U2_gg(X, Xs, Ys, member_in_gg(X, Ys))
member_in_gg(X, .(Y, Xs)) → U1_gg(X, Y, Xs, member_in_gg(X, Xs))
member_in_gg(X, .(X, Xs)) → member_out_gg(X, .(X, Xs))
U1_gg(X, Y, Xs, member_out_gg(X, Xs)) → member_out_gg(X, .(Y, Xs))
U2_gg(X, Xs, Ys, member_out_gg(X, Ys)) → U3_gg(X, Xs, Ys, subset_in_gg(Xs, Ys))
subset_in_gg([], Ys) → subset_out_gg([], Ys)
U3_gg(X, Xs, Ys, subset_out_gg(Xs, Ys)) → subset_out_gg(.(X, Xs), Ys)

The argument filtering Pi contains the following mapping:
subset_in_gg(x1, x2)  =  subset_in_gg(x1, x2)
.(x1, x2)  =  .(x1, x2)
U2_gg(x1, x2, x3, x4)  =  U2_gg(x2, x3, x4)
member_in_gg(x1, x2)  =  member_in_gg(x1, x2)
U1_gg(x1, x2, x3, x4)  =  U1_gg(x4)
member_out_gg(x1, x2)  =  member_out_gg
U3_gg(x1, x2, x3, x4)  =  U3_gg(x4)
[]  =  []
subset_out_gg(x1, x2)  =  subset_out_gg
U1_GG(x1, x2, x3, x4)  =  U1_GG(x4)
MEMBER_IN_GG(x1, x2)  =  MEMBER_IN_GG(x1, x2)
SUBSET_IN_GG(x1, x2)  =  SUBSET_IN_GG(x1, x2)
U2_GG(x1, x2, x3, x4)  =  U2_GG(x2, x3, x4)
U3_GG(x1, x2, x3, x4)  =  U3_GG(x4)

We have to consider all (P,R,Pi)-chains
The approximation of the Dependency Graph [30] contains 2 SCCs with 3 less nodes.

↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
              ↳ PiDP
                ↳ UsableRulesProof
              ↳ PiDP

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

MEMBER_IN_GG(X, .(Y, Xs)) → MEMBER_IN_GG(X, Xs)

The TRS R consists of the following rules:

subset_in_gg(.(X, Xs), Ys) → U2_gg(X, Xs, Ys, member_in_gg(X, Ys))
member_in_gg(X, .(Y, Xs)) → U1_gg(X, Y, Xs, member_in_gg(X, Xs))
member_in_gg(X, .(X, Xs)) → member_out_gg(X, .(X, Xs))
U1_gg(X, Y, Xs, member_out_gg(X, Xs)) → member_out_gg(X, .(Y, Xs))
U2_gg(X, Xs, Ys, member_out_gg(X, Ys)) → U3_gg(X, Xs, Ys, subset_in_gg(Xs, Ys))
subset_in_gg([], Ys) → subset_out_gg([], Ys)
U3_gg(X, Xs, Ys, subset_out_gg(Xs, Ys)) → subset_out_gg(.(X, Xs), Ys)

The argument filtering Pi contains the following mapping:
subset_in_gg(x1, x2)  =  subset_in_gg(x1, x2)
.(x1, x2)  =  .(x1, x2)
U2_gg(x1, x2, x3, x4)  =  U2_gg(x2, x3, x4)
member_in_gg(x1, x2)  =  member_in_gg(x1, x2)
U1_gg(x1, x2, x3, x4)  =  U1_gg(x4)
member_out_gg(x1, x2)  =  member_out_gg
U3_gg(x1, x2, x3, x4)  =  U3_gg(x4)
[]  =  []
subset_out_gg(x1, x2)  =  subset_out_gg
MEMBER_IN_GG(x1, x2)  =  MEMBER_IN_GG(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

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

MEMBER_IN_GG(X, .(Y, Xs)) → MEMBER_IN_GG(X, Xs)

R is empty.
Pi is empty.
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

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

MEMBER_IN_GG(X, .(Y, Xs)) → MEMBER_IN_GG(X, Xs)

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: 



↳ Prolog
  ↳ PrologToPiTRSProof
    ↳ PiTRS
      ↳ DependencyPairsProof
        ↳ PiDP
          ↳ DependencyGraphProof
            ↳ AND
              ↳ PiDP
              ↳ PiDP
                ↳ UsableRulesProof

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

SUBSET_IN_GG(.(X, Xs), Ys) → U2_GG(X, Xs, Ys, member_in_gg(X, Ys))
U2_GG(X, Xs, Ys, member_out_gg(X, Ys)) → SUBSET_IN_GG(Xs, Ys)

The TRS R consists of the following rules:

subset_in_gg(.(X, Xs), Ys) → U2_gg(X, Xs, Ys, member_in_gg(X, Ys))
member_in_gg(X, .(Y, Xs)) → U1_gg(X, Y, Xs, member_in_gg(X, Xs))
member_in_gg(X, .(X, Xs)) → member_out_gg(X, .(X, Xs))
U1_gg(X, Y, Xs, member_out_gg(X, Xs)) → member_out_gg(X, .(Y, Xs))
U2_gg(X, Xs, Ys, member_out_gg(X, Ys)) → U3_gg(X, Xs, Ys, subset_in_gg(Xs, Ys))
subset_in_gg([], Ys) → subset_out_gg([], Ys)
U3_gg(X, Xs, Ys, subset_out_gg(Xs, Ys)) → subset_out_gg(.(X, Xs), Ys)

The argument filtering Pi contains the following mapping:
subset_in_gg(x1, x2)  =  subset_in_gg(x1, x2)
.(x1, x2)  =  .(x1, x2)
U2_gg(x1, x2, x3, x4)  =  U2_gg(x2, x3, x4)
member_in_gg(x1, x2)  =  member_in_gg(x1, x2)
U1_gg(x1, x2, x3, x4)  =  U1_gg(x4)
member_out_gg(x1, x2)  =  member_out_gg
U3_gg(x1, x2, x3, x4)  =  U3_gg(x4)
[]  =  []
subset_out_gg(x1, x2)  =  subset_out_gg
SUBSET_IN_GG(x1, x2)  =  SUBSET_IN_GG(x1, x2)
U2_GG(x1, x2, x3, x4)  =  U2_GG(x2, x3, x4)

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

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

SUBSET_IN_GG(.(X, Xs), Ys) → U2_GG(X, Xs, Ys, member_in_gg(X, Ys))
U2_GG(X, Xs, Ys, member_out_gg(X, Ys)) → SUBSET_IN_GG(Xs, Ys)

The TRS R consists of the following rules:

member_in_gg(X, .(Y, Xs)) → U1_gg(X, Y, Xs, member_in_gg(X, Xs))
member_in_gg(X, .(X, Xs)) → member_out_gg(X, .(X, Xs))
U1_gg(X, Y, Xs, member_out_gg(X, Xs)) → member_out_gg(X, .(Y, Xs))

The argument filtering Pi contains the following mapping:
.(x1, x2)  =  .(x1, x2)
member_in_gg(x1, x2)  =  member_in_gg(x1, x2)
U1_gg(x1, x2, x3, x4)  =  U1_gg(x4)
member_out_gg(x1, x2)  =  member_out_gg
SUBSET_IN_GG(x1, x2)  =  SUBSET_IN_GG(x1, x2)
U2_GG(x1, x2, x3, x4)  =  U2_GG(x2, x3, x4)

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
                        ↳ QDPSizeChangeProof

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

U2_GG(Xs, Ys, member_out_gg) → SUBSET_IN_GG(Xs, Ys)
SUBSET_IN_GG(.(X, Xs), Ys) → U2_GG(Xs, Ys, member_in_gg(X, Ys))

The TRS R consists of the following rules:

member_in_gg(X, .(Y, Xs)) → U1_gg(member_in_gg(X, Xs))
member_in_gg(X, .(X, Xs)) → member_out_gg
U1_gg(member_out_gg) → member_out_gg

The set Q consists of the following terms:

member_in_gg(x0, x1)
U1_gg(x0)

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: