(0) Obligation:

The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(1, n^1).


The TRS R consists of the following rules:

++(nil, y) → y
++(x, nil) → x
++(.(x, y), z) → .(x, ++(y, z))
++(++(x, y), z) → ++(x, ++(y, z))

Rewrite Strategy: INNERMOST

(1) NestedDefinedSymbolProof (BOTH BOUNDS(ID, ID) transformation)

The TRS does not nest defined symbols.
Hence, the left-hand sides of the following rules are not basic-reachable and can be removed:
++(++(x, y), z) → ++(x, ++(y, z))

(2) Obligation:

The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(1, n^1).


The TRS R consists of the following rules:

++(.(x, y), z) → .(x, ++(y, z))
++(nil, y) → y
++(x, nil) → x

Rewrite Strategy: INNERMOST

(3) TrsToWeightedTrsProof (BOTH BOUNDS(ID, ID) transformation)

Transformed TRS to weighted TRS

(4) Obligation:

The Runtime Complexity (innermost) of the given CpxWeightedTrs could be proven to be BOUNDS(1, n^1).


The TRS R consists of the following rules:

++(.(x, y), z) → .(x, ++(y, z)) [1]
++(nil, y) → y [1]
++(x, nil) → x [1]

Rewrite Strategy: INNERMOST

(5) TypeInferenceProof (BOTH BOUNDS(ID, ID) transformation)

Infered types.

(6) Obligation:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

++(.(x, y), z) → .(x, ++(y, z)) [1]
++(nil, y) → y [1]
++(x, nil) → x [1]

The TRS has the following type information:
++ :: .:nil → .:nil → .:nil
. :: a → .:nil → .:nil
nil :: .:nil

Rewrite Strategy: INNERMOST

(7) CompletionProof (UPPER BOUND(ID) transformation)

The transformation into a RNTS is sound, since:

(a) The obligation is a constructor system where every type has a constant constructor,

(b) The following defined symbols do not have to be completely defined, as they can never occur inside other defined symbols:


++

(c) The following functions are completely defined:
none

Due to the following rules being added:
none

And the following fresh constants:

const

(8) Obligation:

Runtime Complexity Weighted TRS where critical functions are completely defined. The underlying TRS is:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

++(.(x, y), z) → .(x, ++(y, z)) [1]
++(nil, y) → y [1]
++(x, nil) → x [1]

The TRS has the following type information:
++ :: .:nil → .:nil → .:nil
. :: a → .:nil → .:nil
nil :: .:nil
const :: a

Rewrite Strategy: INNERMOST

(9) NarrowingProof (BOTH BOUNDS(ID, ID) transformation)

Narrowed the inner basic terms of all right-hand sides by a single narrowing step.

(10) Obligation:

Runtime Complexity Weighted TRS where critical functions are completely defined. The underlying TRS is:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

++(.(x, y), z) → .(x, ++(y, z)) [1]
++(nil, y) → y [1]
++(x, nil) → x [1]

The TRS has the following type information:
++ :: .:nil → .:nil → .:nil
. :: a → .:nil → .:nil
nil :: .:nil
const :: a

Rewrite Strategy: INNERMOST

(11) CpxTypedWeightedTrsToRntsProof (UPPER BOUND(ID) transformation)

Transformed the TRS into an over-approximating RNTS by (improved) Size Abstraction.
The constant constructors are abstracted as follows:

nil => 0
const => 0

(12) Obligation:

Complexity RNTS consisting of the following rules:

++(z', z'') -{ 1 }→ x :|: z'' = 0, z' = x, x >= 0
++(z', z'') -{ 1 }→ y :|: z'' = y, y >= 0, z' = 0
++(z', z'') -{ 1 }→ 1 + x + ++(y, z) :|: z'' = z, z >= 0, z' = 1 + x + y, x >= 0, y >= 0

(13) SimplificationProof (BOTH BOUNDS(ID, ID) transformation)

Simplified the RNTS by moving equalities from the constraints into the right-hand sides.

(14) Obligation:

Complexity RNTS consisting of the following rules:

++(z', z'') -{ 1 }→ z' :|: z'' = 0, z' >= 0
++(z', z'') -{ 1 }→ z'' :|: z'' >= 0, z' = 0
++(z', z'') -{ 1 }→ 1 + x + ++(y, z'') :|: z'' >= 0, z' = 1 + x + y, x >= 0, y >= 0

(15) CpxRntsAnalysisOrderProof (BOTH BOUNDS(ID, ID) transformation)

Found the following analysis order by SCC decomposition:

{ ++ }

(16) Obligation:

Complexity RNTS consisting of the following rules:

++(z', z'') -{ 1 }→ z' :|: z'' = 0, z' >= 0
++(z', z'') -{ 1 }→ z'' :|: z'' >= 0, z' = 0
++(z', z'') -{ 1 }→ 1 + x + ++(y, z'') :|: z'' >= 0, z' = 1 + x + y, x >= 0, y >= 0

Function symbols to be analyzed: {++}

(17) IntTrsBoundProof (UPPER BOUND(ID) transformation)


Computed SIZE bound using CoFloCo for: ++
after applying outer abstraction to obtain an ITS,
resulting in: O(n1) with polynomial bound: z' + z''

(18) Obligation:

Complexity RNTS consisting of the following rules:

++(z', z'') -{ 1 }→ z' :|: z'' = 0, z' >= 0
++(z', z'') -{ 1 }→ z'' :|: z'' >= 0, z' = 0
++(z', z'') -{ 1 }→ 1 + x + ++(y, z'') :|: z'' >= 0, z' = 1 + x + y, x >= 0, y >= 0

Function symbols to be analyzed: {++}
Previous analysis results are:
++: runtime: ?, size: O(n1) [z' + z'']

(19) IntTrsBoundProof (UPPER BOUND(ID) transformation)


Computed RUNTIME bound using CoFloCo for: ++
after applying outer abstraction to obtain an ITS,
resulting in: O(n1) with polynomial bound: 1 + z'

(20) Obligation:

Complexity RNTS consisting of the following rules:

++(z', z'') -{ 1 }→ z' :|: z'' = 0, z' >= 0
++(z', z'') -{ 1 }→ z'' :|: z'' >= 0, z' = 0
++(z', z'') -{ 1 }→ 1 + x + ++(y, z'') :|: z'' >= 0, z' = 1 + x + y, x >= 0, y >= 0

Function symbols to be analyzed:
Previous analysis results are:
++: runtime: O(n1) [1 + z'], size: O(n1) [z' + z'']

(21) FinalProof (EQUIVALENT transformation)

Computed overall runtime complexity

(22) BOUNDS(1, n^1)