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

(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:

f(a, a) → f(a, b)
f(a, b) → f(s(a), c)
f(s(X), c) → f(X, c)
f(c, c) → f(a, a)

Rewrite Strategy: INNERMOST

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

Transformed TRS to weighted TRS

(2) 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:

f(a, a) → f(a, b) [1]
f(a, b) → f(s(a), c) [1]
f(s(X), c) → f(X, c) [1]
f(c, c) → f(a, a) [1]

Rewrite Strategy: INNERMOST

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

Infered types.

(4) Obligation:

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

f(a, a) → f(a, b) [1]
f(a, b) → f(s(a), c) [1]
f(s(X), c) → f(X, c) [1]
f(c, c) → f(a, a) [1]

The TRS has the following type information:

f :: a:b:s:c → a:b:s:c → f a :: a:b:s:c b :: a:b:s:c s :: a:b:s:c → a:b:s:c c :: a:b:s:c

Rewrite Strategy: INNERMOST

(5) 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:

f

(c) The following functions are completely defined:
none

Due to the following rules being added:
none

And the following fresh constants:

const

(6) 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: f(a, a) → f(a, b) [1] f(a, b) → f(s(a), c) [1] f(s(X), c) → f(X, c) [1] f(c, c) → f(a, a) [1] The TRS has the following type information: f :: a:b:s:c → a:b:s:c → f a :: a:b:s:c b :: a:b:s:c s :: a:b:s:c → a:b:s:c c :: a:b:s:c const :: f Rewrite Strategy: INNERMOST

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

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

(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: f(a, a) → f(a, b) [1] f(a, b) → f(s(a), c) [1] f(s(X), c) → f(X, c) [1] f(c, c) → f(a, a) [1] The TRS has the following type information: f :: a:b:s:c → a:b:s:c → f a :: a:b:s:c b :: a:b:s:c s :: a:b:s:c → a:b:s:c c :: a:b:s:c const :: f Rewrite Strategy: INNERMOST

(9) CpxTypedWeightedTrsToRntsProof (UPPER BOUND(ID) transformation)

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

a => 0
b => 1
c => 2
const => 0

(10) Obligation:

Complexity RNTS consisting of the following rules:

f(z, z') -{ 1 }→ f(X, 2) :|: z = 1 + X, z' = 2, X >= 0
f(z, z') -{ 1 }→ f(0, 1) :|: z = 0, z' = 0
f(z, z') -{ 1 }→ f(0, 0) :|: z = 2, z' = 2
f(z, z') -{ 1 }→ f(1 + 0, 2) :|: z' = 1, z = 0

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

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

(12) Obligation:

Complexity RNTS consisting of the following rules:

f(z, z') -{ 1 }→ f(0, 1) :|: z = 0, z' = 0
f(z, z') -{ 1 }→ f(0, 0) :|: z = 2, z' = 2
f(z, z') -{ 1 }→ f(z - 1, 2) :|: z' = 2, z - 1 >= 0
f(z, z') -{ 1 }→ f(1 + 0, 2) :|: z' = 1, z = 0

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

Found the following analysis order by SCC decomposition:

{ f }

(14) Obligation:

Complexity RNTS consisting of the following rules:

f(z, z') -{ 1 }→ f(0, 1) :|: z = 0, z' = 0
f(z, z') -{ 1 }→ f(0, 0) :|: z = 2, z' = 2
f(z, z') -{ 1 }→ f(z - 1, 2) :|: z' = 2, z - 1 >= 0
f(z, z') -{ 1 }→ f(1 + 0, 2) :|: z' = 1, z = 0

Function symbols to be analyzed: {f}

(15) IntTrsBoundProof (UPPER BOUND(ID) transformation)

Computed SIZE bound using CoFloCo for: f
after applying outer abstraction to obtain an ITS,
resulting in: O(1) with polynomial bound: 0

(16) Obligation:

Complexity RNTS consisting of the following rules:

f(z, z') -{ 1 }→ f(0, 1) :|: z = 0, z' = 0
f(z, z') -{ 1 }→ f(0, 0) :|: z = 2, z' = 2
f(z, z') -{ 1 }→ f(z - 1, 2) :|: z' = 2, z - 1 >= 0
f(z, z') -{ 1 }→ f(1 + 0, 2) :|: z' = 1, z = 0

Function symbols to be analyzed: {f}
Previous analysis results are:

f: runtime: ?, size: O(1) [0]

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

Computed RUNTIME bound using KoAT for: f
after applying outer abstraction to obtain an ITS,
resulting in: O(n¹) with polynomial bound: 10 + 4·z

(18) Obligation:

Complexity RNTS consisting of the following rules:

f(z, z') -{ 1 }→ f(0, 1) :|: z = 0, z' = 0
f(z, z') -{ 1 }→ f(0, 0) :|: z = 2, z' = 2
f(z, z') -{ 1 }→ f(z - 1, 2) :|: z' = 2, z - 1 >= 0
f(z, z') -{ 1 }→ f(1 + 0, 2) :|: z' = 1, z = 0

Function symbols to be analyzed:
Previous analysis results are:

f: runtime: O(n1) [10 + 4·z], size: O(1) [0]

(19) FinalProof (EQUIVALENT transformation)

Computed overall runtime complexity

(20) BOUNDS(1, n^1)