YES

Problem:
 a__zeros() -> cons(0(),zeros())
 a__U11(tt()) -> tt()
 a__U21(tt()) -> tt()
 a__U31(tt()) -> tt()
 a__U41(tt(),V2) -> a__U42(a__isNatIList(V2))
 a__U42(tt()) -> tt()
 a__U51(tt(),V2) -> a__U52(a__isNatList(V2))
 a__U52(tt()) -> tt()
 a__U61(tt(),L,N) -> a__U62(a__isNat(N),L)
 a__U62(tt(),L) -> s(a__length(mark(L)))
 a__isNat(0()) -> tt()
 a__isNat(length(V1)) -> a__U11(a__isNatList(V1))
 a__isNat(s(V1)) -> a__U21(a__isNat(V1))
 a__isNatIList(V) -> a__U31(a__isNatList(V))
 a__isNatIList(zeros()) -> tt()
 a__isNatIList(cons(V1,V2)) -> a__U41(a__isNat(V1),V2)
 a__isNatList(nil()) -> tt()
 a__isNatList(cons(V1,V2)) -> a__U51(a__isNat(V1),V2)
 a__length(nil()) -> 0()
 a__length(cons(N,L)) -> a__U61(a__isNatList(L),L,N)
 mark(zeros()) -> a__zeros()
 mark(U11(X)) -> a__U11(mark(X))
 mark(U21(X)) -> a__U21(mark(X))
 mark(U31(X)) -> a__U31(mark(X))
 mark(U41(X1,X2)) -> a__U41(mark(X1),X2)
 mark(U42(X)) -> a__U42(mark(X))
 mark(isNatIList(X)) -> a__isNatIList(X)
 mark(U51(X1,X2)) -> a__U51(mark(X1),X2)
 mark(U52(X)) -> a__U52(mark(X))
 mark(isNatList(X)) -> a__isNatList(X)
 mark(U61(X1,X2,X3)) -> a__U61(mark(X1),X2,X3)
 mark(U62(X1,X2)) -> a__U62(mark(X1),X2)
 mark(isNat(X)) -> a__isNat(X)
 mark(length(X)) -> a__length(mark(X))
 mark(cons(X1,X2)) -> cons(mark(X1),X2)
 mark(0()) -> 0()
 mark(tt()) -> tt()
 mark(s(X)) -> s(mark(X))
 mark(nil()) -> nil()
 a__zeros() -> zeros()
 a__U11(X) -> U11(X)
 a__U21(X) -> U21(X)
 a__U31(X) -> U31(X)
 a__U41(X1,X2) -> U41(X1,X2)
 a__U42(X) -> U42(X)
 a__isNatIList(X) -> isNatIList(X)
 a__U51(X1,X2) -> U51(X1,X2)
 a__U52(X) -> U52(X)
 a__isNatList(X) -> isNatList(X)
 a__U61(X1,X2,X3) -> U61(X1,X2,X3)
 a__U62(X1,X2) -> U62(X1,X2)
 a__isNat(X) -> isNat(X)
 a__length(X) -> length(X)

Proof:
 Matrix Interpretation Processor: dim=1
  
  interpretation:
   [a__length](x0) = 2x0 + 4,
   
   [tt] = 0,
   
   [a__isNat](x0) = 2x0,
   
   [a__U41](x0, x1) = x0 + 4x1,
   
   [0] = 0,
   
   [cons](x0, x1) = 2x0 + 4x1 + 1,
   
   [a__U62](x0, x1) = x0 + 4x1 + 6,
   
   [nil] = 2,
   
   [U42](x0) = x0,
   
   [U62](x0, x1) = x0 + 4x1 + 4,
   
   [s](x0) = x0,
   
   [mark](x0) = 2x0 + 1,
   
   [isNatIList](x0) = 4x0,
   
   [U11](x0) = x0 + 1,
   
   [U51](x0, x1) = 2x0 + 2x1 + 3,
   
   [a__U11](x0) = x0 + 2,
   
   [isNat](x0) = x0,
   
   [a__U42](x0) = x0,
   
   [a__zeros] = 1,
   
   [a__U31](x0) = x0,
   
   [length](x0) = 2x0 + 4,
   
   [U41](x0, x1) = x0 + 4x1,
   
   [isNatList](x0) = 4x0,
   
   [a__U61](x0, x1, x2) = x0 + 4x1 + 3x2 + 6,
   
   [U61](x0, x1, x2) = x0 + 4x1 + 2x2 + 4,
   
   [a__isNatList](x0) = 4x0,
   
   [U21](x0) = x0,
   
   [U31](x0) = x0,
   
   [a__U51](x0, x1) = 2x0 + 4x1 + 4,
   
   [a__isNatIList](x0) = 4x0,
   
   [a__U52](x0) = x0 + 2,
   
   [a__U21](x0) = x0,
   
   [U52](x0) = x0 + 2,
   
   [zeros] = 0
  orientation:
   a__zeros() = 1 >= 1 = cons(0(),zeros())
   
   a__U11(tt()) = 2 >= 0 = tt()
   
   a__U21(tt()) = 0 >= 0 = tt()
   
   a__U31(tt()) = 0 >= 0 = tt()
   
   a__U41(tt(),V2) = 4V2 >= 4V2 = a__U42(a__isNatIList(V2))
   
   a__U42(tt()) = 0 >= 0 = tt()
   
   a__U51(tt(),V2) = 4V2 + 4 >= 4V2 + 2 = a__U52(a__isNatList(V2))
   
   a__U52(tt()) = 2 >= 0 = tt()
   
   a__U61(tt(),L,N) = 4L + 3N + 6 >= 4L + 2N + 6 = a__U62(a__isNat(N),L)
   
   a__U62(tt(),L) = 4L + 6 >= 4L + 6 = s(a__length(mark(L)))
   
   a__isNat(0()) = 0 >= 0 = tt()
   
   a__isNat(length(V1)) = 4V1 + 8 >= 4V1 + 2 = a__U11(a__isNatList(V1))
   
   a__isNat(s(V1)) = 2V1 >= 2V1 = a__U21(a__isNat(V1))
   
   a__isNatIList(V) = 4V >= 4V = a__U31(a__isNatList(V))
   
   a__isNatIList(zeros()) = 0 >= 0 = tt()
   
   a__isNatIList(cons(V1,V2)) = 8V1 + 16V2 + 4 >= 2V1 + 4V2 = a__U41(a__isNat(V1),V2)
   
   a__isNatList(nil()) = 8 >= 0 = tt()
   
   a__isNatList(cons(V1,V2)) = 8V1 + 16V2 + 4 >= 4V1 + 4V2 + 4 = a__U51(a__isNat(V1),V2)
   
   a__length(nil()) = 8 >= 0 = 0()
   
   a__length(cons(N,L)) = 8L + 4N + 6 >= 8L + 3N + 6 = a__U61(a__isNatList(L),L,N)
   
   mark(zeros()) = 1 >= 1 = a__zeros()
   
   mark(U11(X)) = 2X + 3 >= 2X + 3 = a__U11(mark(X))
   
   mark(U21(X)) = 2X + 1 >= 2X + 1 = a__U21(mark(X))
   
   mark(U31(X)) = 2X + 1 >= 2X + 1 = a__U31(mark(X))
   
   mark(U41(X1,X2)) = 2X1 + 8X2 + 1 >= 2X1 + 4X2 + 1 = a__U41(mark(X1),X2)
   
   mark(U42(X)) = 2X + 1 >= 2X + 1 = a__U42(mark(X))
   
   mark(isNatIList(X)) = 8X + 1 >= 4X = a__isNatIList(X)
   
   mark(U51(X1,X2)) = 4X1 + 4X2 + 7 >= 4X1 + 4X2 + 6 = a__U51(mark(X1),X2)
   
   mark(U52(X)) = 2X + 5 >= 2X + 3 = a__U52(mark(X))
   
   mark(isNatList(X)) = 8X + 1 >= 4X = a__isNatList(X)
   
   mark(U61(X1,X2,X3)) = 2X1 + 8X2 + 4X3 + 9 >= 2X1 + 4X2 + 3X3 + 7 = a__U61(mark(X1),X2,X3)
   
   mark(U62(X1,X2)) = 2X1 + 8X2 + 9 >= 2X1 + 4X2 + 7 = a__U62(mark(X1),X2)
   
   mark(isNat(X)) = 2X + 1 >= 2X = a__isNat(X)
   
   mark(length(X)) = 4X + 9 >= 4X + 6 = a__length(mark(X))
   
   mark(cons(X1,X2)) = 4X1 + 8X2 + 3 >= 4X1 + 4X2 + 3 = cons(mark(X1),X2)
   
   mark(0()) = 1 >= 0 = 0()
   
   mark(tt()) = 1 >= 0 = tt()
   
   mark(s(X)) = 2X + 1 >= 2X + 1 = s(mark(X))
   
   mark(nil()) = 5 >= 2 = nil()
   
   a__zeros() = 1 >= 0 = zeros()
   
   a__U11(X) = X + 2 >= X + 1 = U11(X)
   
   a__U21(X) = X >= X = U21(X)
   
   a__U31(X) = X >= X = U31(X)
   
   a__U41(X1,X2) = X1 + 4X2 >= X1 + 4X2 = U41(X1,X2)
   
   a__U42(X) = X >= X = U42(X)
   
   a__isNatIList(X) = 4X >= 4X = isNatIList(X)
   
   a__U51(X1,X2) = 2X1 + 4X2 + 4 >= 2X1 + 2X2 + 3 = U51(X1,X2)
   
   a__U52(X) = X + 2 >= X + 2 = U52(X)
   
   a__isNatList(X) = 4X >= 4X = isNatList(X)
   
   a__U61(X1,X2,X3) = X1 + 4X2 + 3X3 + 6 >= X1 + 4X2 + 2X3 + 4 = U61(X1,X2,X3)
   
   a__U62(X1,X2) = X1 + 4X2 + 6 >= X1 + 4X2 + 4 = U62(X1,X2)
   
   a__isNat(X) = 2X >= X = isNat(X)
   
   a__length(X) = 2X + 4 >= 2X + 4 = length(X)
  problem:
   a__zeros() -> cons(0(),zeros())
   a__U21(tt()) -> tt()
   a__U31(tt()) -> tt()
   a__U41(tt(),V2) -> a__U42(a__isNatIList(V2))
   a__U42(tt()) -> tt()
   a__U61(tt(),L,N) -> a__U62(a__isNat(N),L)
   a__U62(tt(),L) -> s(a__length(mark(L)))
   a__isNat(0()) -> tt()
   a__isNat(s(V1)) -> a__U21(a__isNat(V1))
   a__isNatIList(V) -> a__U31(a__isNatList(V))
   a__isNatIList(zeros()) -> tt()
   a__isNatList(cons(V1,V2)) -> a__U51(a__isNat(V1),V2)
   a__length(cons(N,L)) -> a__U61(a__isNatList(L),L,N)
   mark(zeros()) -> a__zeros()
   mark(U11(X)) -> a__U11(mark(X))
   mark(U21(X)) -> a__U21(mark(X))
   mark(U31(X)) -> a__U31(mark(X))
   mark(U41(X1,X2)) -> a__U41(mark(X1),X2)
   mark(U42(X)) -> a__U42(mark(X))
   mark(cons(X1,X2)) -> cons(mark(X1),X2)
   mark(s(X)) -> s(mark(X))
   a__U21(X) -> U21(X)
   a__U31(X) -> U31(X)
   a__U41(X1,X2) -> U41(X1,X2)
   a__U42(X) -> U42(X)
   a__isNatIList(X) -> isNatIList(X)
   a__U52(X) -> U52(X)
   a__isNatList(X) -> isNatList(X)
   a__isNat(X) -> isNat(X)
   a__length(X) -> length(X)
  Matrix Interpretation Processor: dim=1
   
   interpretation:
    [a__length](x0) = x0,
    
    [tt] = 0,
    
    [a__isNat](x0) = x0,
    
    [a__U41](x0, x1) = x0 + 4x1 + 2,
    
    [0] = 0,
    
    [cons](x0, x1) = x0 + 6x1,
    
    [a__U62](x0, x1) = x0 + 4x1,
    
    [U42](x0) = 2x0,
    
    [s](x0) = 2x0,
    
    [mark](x0) = 2x0,
    
    [isNatIList](x0) = x0,
    
    [U11](x0) = 4x0 + 4,
    
    [a__U11](x0) = x0,
    
    [isNat](x0) = x0,
    
    [a__U42](x0) = 2x0,
    
    [a__zeros] = 0,
    
    [a__U31](x0) = x0,
    
    [length](x0) = x0,
    
    [U41](x0, x1) = x0 + 4x1 + 1,
    
    [isNatList](x0) = 2x0,
    
    [a__U61](x0, x1, x2) = x0 + 4x1 + x2,
    
    [a__isNatList](x0) = 2x0,
    
    [U21](x0) = x0,
    
    [U31](x0) = x0,
    
    [a__U51](x0, x1) = x0 + 2x1,
    
    [a__isNatIList](x0) = 2x0,
    
    [a__U52](x0) = x0 + 4,
    
    [a__U21](x0) = x0,
    
    [U52](x0) = x0,
    
    [zeros] = 0
   orientation:
    a__zeros() = 0 >= 0 = cons(0(),zeros())
    
    a__U21(tt()) = 0 >= 0 = tt()
    
    a__U31(tt()) = 0 >= 0 = tt()
    
    a__U41(tt(),V2) = 4V2 + 2 >= 4V2 = a__U42(a__isNatIList(V2))
    
    a__U42(tt()) = 0 >= 0 = tt()
    
    a__U61(tt(),L,N) = 4L + N >= 4L + N = a__U62(a__isNat(N),L)
    
    a__U62(tt(),L) = 4L >= 4L = s(a__length(mark(L)))
    
    a__isNat(0()) = 0 >= 0 = tt()
    
    a__isNat(s(V1)) = 2V1 >= V1 = a__U21(a__isNat(V1))
    
    a__isNatIList(V) = 2V >= 2V = a__U31(a__isNatList(V))
    
    a__isNatIList(zeros()) = 0 >= 0 = tt()
    
    a__isNatList(cons(V1,V2)) = 2V1 + 12V2 >= V1 + 2V2 = a__U51(a__isNat(V1),V2)
    
    a__length(cons(N,L)) = 6L + N >= 6L + N = a__U61(a__isNatList(L),L,N)
    
    mark(zeros()) = 0 >= 0 = a__zeros()
    
    mark(U11(X)) = 8X + 8 >= 2X = a__U11(mark(X))
    
    mark(U21(X)) = 2X >= 2X = a__U21(mark(X))
    
    mark(U31(X)) = 2X >= 2X = a__U31(mark(X))
    
    mark(U41(X1,X2)) = 2X1 + 8X2 + 2 >= 2X1 + 4X2 + 2 = a__U41(mark(X1),X2)
    
    mark(U42(X)) = 4X >= 4X = a__U42(mark(X))
    
    mark(cons(X1,X2)) = 2X1 + 12X2 >= 2X1 + 6X2 = cons(mark(X1),X2)
    
    mark(s(X)) = 4X >= 4X = s(mark(X))
    
    a__U21(X) = X >= X = U21(X)
    
    a__U31(X) = X >= X = U31(X)
    
    a__U41(X1,X2) = X1 + 4X2 + 2 >= X1 + 4X2 + 1 = U41(X1,X2)
    
    a__U42(X) = 2X >= 2X = U42(X)
    
    a__isNatIList(X) = 2X >= X = isNatIList(X)
    
    a__U52(X) = X + 4 >= X = U52(X)
    
    a__isNatList(X) = 2X >= 2X = isNatList(X)
    
    a__isNat(X) = X >= X = isNat(X)
    
    a__length(X) = X >= X = length(X)
   problem:
    a__zeros() -> cons(0(),zeros())
    a__U21(tt()) -> tt()
    a__U31(tt()) -> tt()
    a__U42(tt()) -> tt()
    a__U61(tt(),L,N) -> a__U62(a__isNat(N),L)
    a__U62(tt(),L) -> s(a__length(mark(L)))
    a__isNat(0()) -> tt()
    a__isNat(s(V1)) -> a__U21(a__isNat(V1))
    a__isNatIList(V) -> a__U31(a__isNatList(V))
    a__isNatIList(zeros()) -> tt()
    a__isNatList(cons(V1,V2)) -> a__U51(a__isNat(V1),V2)
    a__length(cons(N,L)) -> a__U61(a__isNatList(L),L,N)
    mark(zeros()) -> a__zeros()
    mark(U21(X)) -> a__U21(mark(X))
    mark(U31(X)) -> a__U31(mark(X))
    mark(U41(X1,X2)) -> a__U41(mark(X1),X2)
    mark(U42(X)) -> a__U42(mark(X))
    mark(cons(X1,X2)) -> cons(mark(X1),X2)
    mark(s(X)) -> s(mark(X))
    a__U21(X) -> U21(X)
    a__U31(X) -> U31(X)
    a__U42(X) -> U42(X)
    a__isNatIList(X) -> isNatIList(X)
    a__isNatList(X) -> isNatList(X)
    a__isNat(X) -> isNat(X)
    a__length(X) -> length(X)
   Matrix Interpretation Processor: dim=1
    
    interpretation:
     [a__length](x0) = x0 + 2,
     
     [tt] = 0,
     
     [a__isNat](x0) = x0,
     
     [a__U41](x0, x1) = 4x0 + 2x1,
     
     [0] = 0,
     
     [cons](x0, x1) = x0 + 4x1,
     
     [a__U62](x0, x1) = x0 + 2x1 + 2,
     
     [U42](x0) = x0 + 2,
     
     [s](x0) = x0,
     
     [mark](x0) = 2x0,
     
     [isNatIList](x0) = 2x0,
     
     [isNat](x0) = x0,
     
     [a__U42](x0) = x0 + 2,
     
     [a__zeros] = 0,
     
     [a__U31](x0) = x0,
     
     [length](x0) = x0,
     
     [U41](x0, x1) = 4x0 + x1,
     
     [isNatList](x0) = x0,
     
     [a__U61](x0, x1, x2) = x0 + 2x1 + x2 + 2,
     
     [a__isNatList](x0) = x0,
     
     [U21](x0) = x0,
     
     [U31](x0) = x0,
     
     [a__U51](x0, x1) = x0 + x1,
     
     [a__isNatIList](x0) = 2x0,
     
     [a__U21](x0) = x0,
     
     [zeros] = 0
    orientation:
     a__zeros() = 0 >= 0 = cons(0(),zeros())
     
     a__U21(tt()) = 0 >= 0 = tt()
     
     a__U31(tt()) = 0 >= 0 = tt()
     
     a__U42(tt()) = 2 >= 0 = tt()
     
     a__U61(tt(),L,N) = 2L + N + 2 >= 2L + N + 2 = a__U62(a__isNat(N),L)
     
     a__U62(tt(),L) = 2L + 2 >= 2L + 2 = s(a__length(mark(L)))
     
     a__isNat(0()) = 0 >= 0 = tt()
     
     a__isNat(s(V1)) = V1 >= V1 = a__U21(a__isNat(V1))
     
     a__isNatIList(V) = 2V >= V = a__U31(a__isNatList(V))
     
     a__isNatIList(zeros()) = 0 >= 0 = tt()
     
     a__isNatList(cons(V1,V2)) = V1 + 4V2 >= V1 + V2 = a__U51(a__isNat(V1),V2)
     
     a__length(cons(N,L)) = 4L + N + 2 >= 3L + N + 2 = a__U61(a__isNatList(L),L,N)
     
     mark(zeros()) = 0 >= 0 = a__zeros()
     
     mark(U21(X)) = 2X >= 2X = a__U21(mark(X))
     
     mark(U31(X)) = 2X >= 2X = a__U31(mark(X))
     
     mark(U41(X1,X2)) = 8X1 + 2X2 >= 8X1 + 2X2 = a__U41(mark(X1),X2)
     
     mark(U42(X)) = 2X + 4 >= 2X + 2 = a__U42(mark(X))
     
     mark(cons(X1,X2)) = 2X1 + 8X2 >= 2X1 + 4X2 = cons(mark(X1),X2)
     
     mark(s(X)) = 2X >= 2X = s(mark(X))
     
     a__U21(X) = X >= X = U21(X)
     
     a__U31(X) = X >= X = U31(X)
     
     a__U42(X) = X + 2 >= X + 2 = U42(X)
     
     a__isNatIList(X) = 2X >= 2X = isNatIList(X)
     
     a__isNatList(X) = X >= X = isNatList(X)
     
     a__isNat(X) = X >= X = isNat(X)
     
     a__length(X) = X + 2 >= X = length(X)
    problem:
     a__zeros() -> cons(0(),zeros())
     a__U21(tt()) -> tt()
     a__U31(tt()) -> tt()
     a__U61(tt(),L,N) -> a__U62(a__isNat(N),L)
     a__U62(tt(),L) -> s(a__length(mark(L)))
     a__isNat(0()) -> tt()
     a__isNat(s(V1)) -> a__U21(a__isNat(V1))
     a__isNatIList(V) -> a__U31(a__isNatList(V))
     a__isNatIList(zeros()) -> tt()
     a__isNatList(cons(V1,V2)) -> a__U51(a__isNat(V1),V2)
     a__length(cons(N,L)) -> a__U61(a__isNatList(L),L,N)
     mark(zeros()) -> a__zeros()
     mark(U21(X)) -> a__U21(mark(X))
     mark(U31(X)) -> a__U31(mark(X))
     mark(U41(X1,X2)) -> a__U41(mark(X1),X2)
     mark(cons(X1,X2)) -> cons(mark(X1),X2)
     mark(s(X)) -> s(mark(X))
     a__U21(X) -> U21(X)
     a__U31(X) -> U31(X)
     a__U42(X) -> U42(X)
     a__isNatIList(X) -> isNatIList(X)
     a__isNatList(X) -> isNatList(X)
     a__isNat(X) -> isNat(X)
    Matrix Interpretation Processor: dim=1
     
     interpretation:
      [a__length](x0) = 2x0 + 5,
      
      [tt] = 5,
      
      [a__isNat](x0) = x0 + 1,
      
      [a__U41](x0, x1) = x0 + 2x1,
      
      [0] = 4,
      
      [cons](x0, x1) = x0 + 6x1,
      
      [a__U62](x0, x1) = 2x0 + 6x1 + 7,
      
      [U42](x0) = x0,
      
      [s](x0) = x0 + 1,
      
      [mark](x0) = 3x0 + 5,
      
      [isNatIList](x0) = x0,
      
      [isNat](x0) = x0,
      
      [a__U42](x0) = x0,
      
      [a__zeros] = 5,
      
      [a__U31](x0) = x0,
      
      [U41](x0, x1) = x0 + 3x1 + 1,
      
      [isNatList](x0) = x0,
      
      [a__U61](x0, x1, x2) = x0 + 6x1 + 2x2 + 4,
      
      [a__isNatList](x0) = 4x0 + 1,
      
      [U21](x0) = x0 + 1,
      
      [U31](x0) = x0,
      
      [a__U51](x0, x1) = x0 + 2x1,
      
      [a__isNatIList](x0) = 4x0 + 5,
      
      [a__U21](x0) = x0 + 1,
      
      [zeros] = 0
     orientation:
      a__zeros() = 5 >= 4 = cons(0(),zeros())
      
      a__U21(tt()) = 6 >= 5 = tt()
      
      a__U31(tt()) = 5 >= 5 = tt()
      
      a__U61(tt(),L,N) = 6L + 2N + 9 >= 6L + 2N + 9 = a__U62(a__isNat(N),L)
      
      a__U62(tt(),L) = 6L + 17 >= 6L + 16 = s(a__length(mark(L)))
      
      a__isNat(0()) = 5 >= 5 = tt()
      
      a__isNat(s(V1)) = V1 + 2 >= V1 + 2 = a__U21(a__isNat(V1))
      
      a__isNatIList(V) = 4V + 5 >= 4V + 1 = a__U31(a__isNatList(V))
      
      a__isNatIList(zeros()) = 5 >= 5 = tt()
      
      a__isNatList(cons(V1,V2)) = 4V1 + 24V2 + 1 >= V1 + 2V2 + 1 = a__U51(a__isNat(V1),V2)
      
      a__length(cons(N,L)) = 12L + 2N + 5 >= 10L + 2N + 5 = a__U61(a__isNatList(L),L,N)
      
      mark(zeros()) = 5 >= 5 = a__zeros()
      
      mark(U21(X)) = 3X + 8 >= 3X + 6 = a__U21(mark(X))
      
      mark(U31(X)) = 3X + 5 >= 3X + 5 = a__U31(mark(X))
      
      mark(U41(X1,X2)) = 3X1 + 9X2 + 8 >= 3X1 + 2X2 + 5 = a__U41(mark(X1),X2)
      
      mark(cons(X1,X2)) = 3X1 + 18X2 + 5 >= 3X1 + 6X2 + 5 = cons(mark(X1),X2)
      
      mark(s(X)) = 3X + 8 >= 3X + 6 = s(mark(X))
      
      a__U21(X) = X + 1 >= X + 1 = U21(X)
      
      a__U31(X) = X >= X = U31(X)
      
      a__U42(X) = X >= X = U42(X)
      
      a__isNatIList(X) = 4X + 5 >= X = isNatIList(X)
      
      a__isNatList(X) = 4X + 1 >= X = isNatList(X)
      
      a__isNat(X) = X + 1 >= X = isNat(X)
     problem:
      a__U31(tt()) -> tt()
      a__U61(tt(),L,N) -> a__U62(a__isNat(N),L)
      a__isNat(0()) -> tt()
      a__isNat(s(V1)) -> a__U21(a__isNat(V1))
      a__isNatIList(zeros()) -> tt()
      a__isNatList(cons(V1,V2)) -> a__U51(a__isNat(V1),V2)
      a__length(cons(N,L)) -> a__U61(a__isNatList(L),L,N)
      mark(zeros()) -> a__zeros()
      mark(U31(X)) -> a__U31(mark(X))
      mark(cons(X1,X2)) -> cons(mark(X1),X2)
      a__U21(X) -> U21(X)
      a__U31(X) -> U31(X)
      a__U42(X) -> U42(X)
     Matrix Interpretation Processor: dim=1
      
      interpretation:
       [a__length](x0) = x0 + 2,
       
       [tt] = 6,
       
       [a__isNat](x0) = x0 + 6,
       
       [0] = 0,
       
       [cons](x0, x1) = x0 + 2x1 + 4,
       
       [a__U62](x0, x1) = x0 + x1,
       
       [U42](x0) = 2x0,
       
       [s](x0) = x0,
       
       [mark](x0) = x0,
       
       [a__U42](x0) = 2x0 + 1,
       
       [a__zeros] = 0,
       
       [a__U31](x0) = x0,
       
       [a__U61](x0, x1, x2) = x0 + x1 + x2,
       
       [a__isNatList](x0) = x0 + 6,
       
       [U21](x0) = x0,
       
       [U31](x0) = x0,
       
       [a__U51](x0, x1) = x0 + 2x1 + 4,
       
       [a__isNatIList](x0) = x0 + 6,
       
       [a__U21](x0) = x0,
       
       [zeros] = 0
      orientation:
       a__U31(tt()) = 6 >= 6 = tt()
       
       a__U61(tt(),L,N) = L + N + 6 >= L + N + 6 = a__U62(a__isNat(N),L)
       
       a__isNat(0()) = 6 >= 6 = tt()
       
       a__isNat(s(V1)) = V1 + 6 >= V1 + 6 = a__U21(a__isNat(V1))
       
       a__isNatIList(zeros()) = 6 >= 6 = tt()
       
       a__isNatList(cons(V1,V2)) = V1 + 2V2 + 10 >= V1 + 2V2 + 10 = a__U51(a__isNat(V1),V2)
       
       a__length(cons(N,L)) = 2L + N + 6 >= 2L + N + 6 = a__U61(a__isNatList(L),L,N)
       
       mark(zeros()) = 0 >= 0 = a__zeros()
       
       mark(U31(X)) = X >= X = a__U31(mark(X))
       
       mark(cons(X1,X2)) = X1 + 2X2 + 4 >= X1 + 2X2 + 4 = cons(mark(X1),X2)
       
       a__U21(X) = X >= X = U21(X)
       
       a__U31(X) = X >= X = U31(X)
       
       a__U42(X) = 2X + 1 >= 2X = U42(X)
      problem:
       a__U31(tt()) -> tt()
       a__U61(tt(),L,N) -> a__U62(a__isNat(N),L)
       a__isNat(0()) -> tt()
       a__isNat(s(V1)) -> a__U21(a__isNat(V1))
       a__isNatIList(zeros()) -> tt()
       a__isNatList(cons(V1,V2)) -> a__U51(a__isNat(V1),V2)
       a__length(cons(N,L)) -> a__U61(a__isNatList(L),L,N)
       mark(zeros()) -> a__zeros()
       mark(U31(X)) -> a__U31(mark(X))
       mark(cons(X1,X2)) -> cons(mark(X1),X2)
       a__U21(X) -> U21(X)
       a__U31(X) -> U31(X)
      Matrix Interpretation Processor: dim=1
       
       interpretation:
        [a__length](x0) = x0 + 2,
        
        [tt] = 1,
        
        [a__isNat](x0) = x0 + 4,
        
        [0] = 0,
        
        [cons](x0, x1) = x0 + 4x1 + 5,
        
        [a__U62](x0, x1) = x0 + 2x1,
        
        [s](x0) = 2x0,
        
        [mark](x0) = x0,
        
        [a__zeros] = 0,
        
        [a__U31](x0) = x0,
        
        [a__U61](x0, x1, x2) = x0 + 2x1 + x2 + 3,
        
        [a__isNatList](x0) = 2x0 + 4,
        
        [U21](x0) = x0,
        
        [U31](x0) = x0,
        
        [a__U51](x0, x1) = 2x0 + x1,
        
        [a__isNatIList](x0) = x0 + 1,
        
        [a__U21](x0) = x0,
        
        [zeros] = 3
       orientation:
        a__U31(tt()) = 1 >= 1 = tt()
        
        a__U61(tt(),L,N) = 2L + N + 4 >= 2L + N + 4 = a__U62(a__isNat(N),L)
        
        a__isNat(0()) = 4 >= 1 = tt()
        
        a__isNat(s(V1)) = 2V1 + 4 >= V1 + 4 = a__U21(a__isNat(V1))
        
        a__isNatIList(zeros()) = 4 >= 1 = tt()
        
        a__isNatList(cons(V1,V2)) = 2V1 + 8V2 + 14 >= 2V1 + V2 + 8 = a__U51(a__isNat(V1),V2)
        
        a__length(cons(N,L)) = 4L + N + 7 >= 4L + N + 7 = a__U61(a__isNatList(L),L,N)
        
        mark(zeros()) = 3 >= 0 = a__zeros()
        
        mark(U31(X)) = X >= X = a__U31(mark(X))
        
        mark(cons(X1,X2)) = X1 + 4X2 + 5 >= X1 + 4X2 + 5 = cons(mark(X1),X2)
        
        a__U21(X) = X >= X = U21(X)
        
        a__U31(X) = X >= X = U31(X)
       problem:
        a__U31(tt()) -> tt()
        a__U61(tt(),L,N) -> a__U62(a__isNat(N),L)
        a__isNat(s(V1)) -> a__U21(a__isNat(V1))
        a__length(cons(N,L)) -> a__U61(a__isNatList(L),L,N)
        mark(U31(X)) -> a__U31(mark(X))
        mark(cons(X1,X2)) -> cons(mark(X1),X2)
        a__U21(X) -> U21(X)
        a__U31(X) -> U31(X)
       Matrix Interpretation Processor: dim=1
        
        interpretation:
         [a__length](x0) = x0 + 1,
         
         [tt] = 0,
         
         [a__isNat](x0) = x0,
         
         [cons](x0, x1) = 4x0 + 4x1,
         
         [a__U62](x0, x1) = x0 + x1,
         
         [s](x0) = 4x0 + 4,
         
         [mark](x0) = 2x0,
         
         [a__U31](x0) = x0,
         
         [a__U61](x0, x1, x2) = x0 + 3x1 + x2,
         
         [a__isNatList](x0) = x0,
         
         [U21](x0) = 4x0,
         
         [U31](x0) = x0,
         
         [a__U21](x0) = 4x0
        orientation:
         a__U31(tt()) = 0 >= 0 = tt()
         
         a__U61(tt(),L,N) = 3L + N >= L + N = a__U62(a__isNat(N),L)
         
         a__isNat(s(V1)) = 4V1 + 4 >= 4V1 = a__U21(a__isNat(V1))
         
         a__length(cons(N,L)) = 4L + 4N + 1 >= 4L + N = a__U61(a__isNatList(L),L,N)
         
         mark(U31(X)) = 2X >= 2X = a__U31(mark(X))
         
         mark(cons(X1,X2)) = 8X1 + 8X2 >= 8X1 + 4X2 = cons(mark(X1),X2)
         
         a__U21(X) = 4X >= 4X = U21(X)
         
         a__U31(X) = X >= X = U31(X)
        problem:
         a__U31(tt()) -> tt()
         a__U61(tt(),L,N) -> a__U62(a__isNat(N),L)
         mark(U31(X)) -> a__U31(mark(X))
         mark(cons(X1,X2)) -> cons(mark(X1),X2)
         a__U21(X) -> U21(X)
         a__U31(X) -> U31(X)
        Matrix Interpretation Processor: dim=3
         
         interpretation:
                 [0]
          [tt] = [1]
                 [1],
          
                           [1 0 0]  
          [a__isNat](x0) = [0 0 0]x0
                           [0 0 0]  ,
          
                           [1 1 1]     [1 0 0]  
          [cons](x0, x1) = [0 0 0]x0 + [0 0 0]x1
                           [0 0 0]     [0 0 0]  ,
          
                             [1 0 0]     [1 0 0]  
          [a__U62](x0, x1) = [0 0 0]x0 + [0 0 0]x1
                             [0 0 0]     [0 0 0]  ,
          
                       [1 0 0]     [1]
          [mark](x0) = [0 0 1]x0 + [0]
                       [0 0 0]     [0],
          
                         [1 0 1]  
          [a__U31](x0) = [0 0 1]x0
                         [0 0 1]  ,
          
                                 [1 0 0]     [1 1 1]     [1 0 0]     [1]
          [a__U61](x0, x1, x2) = [0 0 0]x0 + [0 1 0]x1 + [1 1 0]x2 + [0]
                                 [0 0 0]     [0 0 0]     [1 0 1]     [0],
          
                      [1 0 0]  
          [U21](x0) = [0 0 0]x0
                      [0 0 0]  ,
          
                      [1 0 1]  
          [U31](x0) = [0 0 0]x0
                      [0 0 0]  ,
          
                         [1 1 1]  
          [a__U21](x0) = [1 0 0]x0
                         [0 1 1]  
         orientation:
                         [1]    [0]       
          a__U31(tt()) = [1] >= [1] = tt()
                         [1]    [1]       
          
                             [1 1 1]    [1 0 0]    [1]    [1 0 0]    [1 0 0]                         
          a__U61(tt(),L,N) = [0 1 0]L + [1 1 0]N + [0] >= [0 0 0]L + [0 0 0]N = a__U62(a__isNat(N),L)
                             [0 0 0]    [1 0 1]    [0]    [0 0 0]    [0 0 0]                         
          
                         [1 0 1]    [1]    [1 0 0]    [1]                  
          mark(U31(X)) = [0 0 0]X + [0] >= [0 0 0]X + [0] = a__U31(mark(X))
                         [0 0 0]    [0]    [0 0 0]    [0]                  
          
                              [1 1 1]     [1 0 0]     [1]    [1 0 1]     [1 0 0]     [1]                    
          mark(cons(X1,X2)) = [0 0 0]X1 + [0 0 0]X2 + [0] >= [0 0 0]X1 + [0 0 0]X2 + [0] = cons(mark(X1),X2)
                              [0 0 0]     [0 0 0]     [0]    [0 0 0]     [0 0 0]     [0]                    
          
                      [1 1 1]     [1 0 0]          
          a__U21(X) = [1 0 0]X >= [0 0 0]X = U21(X)
                      [0 1 1]     [0 0 0]          
          
                      [1 0 1]     [1 0 1]          
          a__U31(X) = [0 0 1]X >= [0 0 0]X = U31(X)
                      [0 0 1]     [0 0 0]          
         problem:
          mark(U31(X)) -> a__U31(mark(X))
          mark(cons(X1,X2)) -> cons(mark(X1),X2)
          a__U21(X) -> U21(X)
          a__U31(X) -> U31(X)
         Matrix Interpretation Processor: dim=1
          
          interpretation:
           [cons](x0, x1) = 2x0 + x1,
           
           [mark](x0) = x0,
           
           [a__U31](x0) = x0,
           
           [U21](x0) = 2x0,
           
           [U31](x0) = x0,
           
           [a__U21](x0) = 4x0 + 1
          orientation:
           mark(U31(X)) = X >= X = a__U31(mark(X))
           
           mark(cons(X1,X2)) = 2X1 + X2 >= 2X1 + X2 = cons(mark(X1),X2)
           
           a__U21(X) = 4X + 1 >= 2X = U21(X)
           
           a__U31(X) = X >= X = U31(X)
          problem:
           mark(U31(X)) -> a__U31(mark(X))
           mark(cons(X1,X2)) -> cons(mark(X1),X2)
           a__U31(X) -> U31(X)
          Matrix Interpretation Processor: dim=1
           
           interpretation:
            [cons](x0, x1) = 2x0 + 3x1,
            
            [mark](x0) = 3x0,
            
            [a__U31](x0) = 2x0 + 2,
            
            [U31](x0) = 2x0 + 2
           orientation:
            mark(U31(X)) = 6X + 6 >= 6X + 2 = a__U31(mark(X))
            
            mark(cons(X1,X2)) = 6X1 + 9X2 >= 6X1 + 3X2 = cons(mark(X1),X2)
            
            a__U31(X) = 2X + 2 >= 2X + 2 = U31(X)
           problem:
            mark(cons(X1,X2)) -> cons(mark(X1),X2)
            a__U31(X) -> U31(X)
           Matrix Interpretation Processor: dim=3
            
            interpretation:
                              [1 0 0]     [1 1 0]     [0]
             [cons](x0, x1) = [0 0 1]x0 + [0 0 0]x1 + [1]
                              [0 1 0]     [0 0 0]     [0],
             
                          [1 1 1]  
             [mark](x0) = [0 1 0]x0
                          [0 0 1]  ,
             
                            [1 0 0]  
             [a__U31](x0) = [0 0 0]x0
                            [0 0 0]  ,
             
                         [1 0 0]  
             [U31](x0) = [0 0 0]x0
                         [0 0 0]  
            orientation:
                                 [1 1 1]     [1 1 0]     [1]    [1 1 1]     [1 1 0]     [0]                    
             mark(cons(X1,X2)) = [0 0 1]X1 + [0 0 0]X2 + [1] >= [0 0 1]X1 + [0 0 0]X2 + [1] = cons(mark(X1),X2)
                                 [0 1 0]     [0 0 0]     [0]    [0 1 0]     [0 0 0]     [0]                    
             
                         [1 0 0]     [1 0 0]          
             a__U31(X) = [0 0 0]X >= [0 0 0]X = U31(X)
                         [0 0 0]     [0 0 0]          
            problem:
             a__U31(X) -> U31(X)
            Matrix Interpretation Processor: dim=3
             
             interpretation:
                             [1 0 0]     [1]
              [a__U31](x0) = [0 0 0]x0 + [0]
                             [0 0 1]     [0],
              
                          [1 0 0]  
              [U31](x0) = [0 0 0]x0
                          [0 0 0]  
             orientation:
                          [1 0 0]    [1]    [1 0 0]          
              a__U31(X) = [0 0 0]X + [0] >= [0 0 0]X = U31(X)
                          [0 0 1]    [0]    [0 0 0]          
             problem:
              
             Qed