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:

average(s(x), y) → average(x, s(y))
average(x, s(s(s(y)))) → s(average(s(x), y))
average(0, 0) → 0
average(0, s(0)) → 0
average(0, s(s(0))) → s(0)

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:

average(s(x), y) → average(x, s(y)) [1]
average(x, s(s(s(y)))) → s(average(s(x), y)) [1]
average(0, 0) → 0 [1]
average(0, s(0)) → 0 [1]
average(0, s(s(0))) → s(0) [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:

average(s(x), y) → average(x, s(y)) [1]
average(x, s(s(s(y)))) → s(average(s(x), y)) [1]
average(0, 0) → 0 [1]
average(0, s(0)) → 0 [1]
average(0, s(s(0))) → s(0) [1]

The TRS has the following type information:

average :: s:0 → s:0 → s:0 s :: s:0 → s:0 0 :: s:0

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:

average

(c) The following functions are completely defined:
none

Due to the following rules being added:
none

And the following fresh constants: none

(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: average(s(x), y) → average(x, s(y)) [1] average(x, s(s(s(y)))) → s(average(s(x), y)) [1] average(0, 0) → 0 [1] average(0, s(0)) → 0 [1] average(0, s(s(0))) → s(0) [1] The TRS has the following type information: average :: s:0 → s:0 → s:0 s :: s:0 → s:0 0 :: s:0 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: average(s(x), y) → average(x, s(y)) [1] average(x, s(s(s(y)))) → s(average(s(x), y)) [1] average(0, 0) → 0 [1] average(0, s(0)) → 0 [1] average(0, s(s(0))) → s(0) [1] The TRS has the following type information: average :: s:0 → s:0 → s:0 s :: s:0 → s:0 0 :: s:0 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:

0 => 0

(10) Obligation:

Complexity RNTS consisting of the following rules:

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

average(z, z') -{ 1 }→ average(z - 1, 1 + z') :|: z - 1 >= 0, z' >= 0
average(z, z') -{ 1 }→ 0 :|: z = 0, z' = 0
average(z, z') -{ 1 }→ 0 :|: z' = 1 + 0, z = 0
average(z, z') -{ 1 }→ 1 + average(1 + z, z' - 3) :|: z >= 0, z' - 3 >= 0
average(z, z') -{ 1 }→ 1 + 0 :|: z' = 1 + (1 + 0), z = 0

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

Found the following analysis order by SCC decomposition:

{ average }

(14) Obligation:

Complexity RNTS consisting of the following rules:

average(z, z') -{ 1 }→ average(z - 1, 1 + z') :|: z - 1 >= 0, z' >= 0
average(z, z') -{ 1 }→ 0 :|: z = 0, z' = 0
average(z, z') -{ 1 }→ 0 :|: z' = 1 + 0, z = 0
average(z, z') -{ 1 }→ 1 + average(1 + z, z' - 3) :|: z >= 0, z' - 3 >= 0
average(z, z') -{ 1 }→ 1 + 0 :|: z' = 1 + (1 + 0), z = 0

Function symbols to be analyzed: {average}

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

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

(16) Obligation:

Complexity RNTS consisting of the following rules:

average(z, z') -{ 1 }→ average(z - 1, 1 + z') :|: z - 1 >= 0, z' >= 0
average(z, z') -{ 1 }→ 0 :|: z = 0, z' = 0
average(z, z') -{ 1 }→ 0 :|: z' = 1 + 0, z = 0
average(z, z') -{ 1 }→ 1 + average(1 + z, z' - 3) :|: z >= 0, z' - 3 >= 0
average(z, z') -{ 1 }→ 1 + 0 :|: z' = 1 + (1 + 0), z = 0

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

average: runtime: ?, size: O(n1) [z + z']

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

Computed RUNTIME bound using PUBS for: average
after applying outer abstraction to obtain an ITS,
resulting in: O(n¹) with polynomial bound: 2 + 2·z + z'

(18) Obligation:

Complexity RNTS consisting of the following rules:

average(z, z') -{ 1 }→ average(z - 1, 1 + z') :|: z - 1 >= 0, z' >= 0
average(z, z') -{ 1 }→ 0 :|: z = 0, z' = 0
average(z, z') -{ 1 }→ 0 :|: z' = 1 + 0, z = 0
average(z, z') -{ 1 }→ 1 + average(1 + z, z' - 3) :|: z >= 0, z' - 3 >= 0
average(z, z') -{ 1 }→ 1 + 0 :|: z' = 1 + (1 + 0), z = 0

Function symbols to be analyzed:
Previous analysis results are:

average: runtime: O(n1) [2 + 2·z + z'], size: O(n1) [z + z']

(19) FinalProof (EQUIVALENT transformation)

Computed overall runtime complexity

(20) BOUNDS(1, n^1)