(0) Obligation:
Runtime Complexity TRS:
The TRS R consists of the following rules:
half(0) → 0
half(s(0)) → 0
half(s(s(x))) → s(half(x))
bits(0) → 0
bits(s(x)) → s(bits(half(s(x))))
Rewrite Strategy: FULL
(1) DecreasingLoopProof (EQUIVALENT transformation)
The following loop(s) give(s) rise to the lower bound Ω(n1):
The rewrite sequence
half(s(s(x))) →+ s(half(x))
gives rise to a decreasing loop by considering the right hand sides subterm at position [0].
The pumping substitution is [x / s(s(x))].
The result substitution is [ ].
(2) BOUNDS(n^1, INF)
(3) RenamingProof (EQUIVALENT transformation)
Renamed function symbols to avoid clashes with predefined symbol.
(4) Obligation:
Runtime Complexity Relative TRS:
The TRS R consists of the following rules:
half(0') → 0'
half(s(0')) → 0'
half(s(s(x))) → s(half(x))
bits(0') → 0'
bits(s(x)) → s(bits(half(s(x))))
S is empty.
Rewrite Strategy: FULL
(5) TypeInferenceProof (BOTH BOUNDS(ID, ID) transformation)
Infered types.
(6) Obligation:
TRS:
Rules:
half(0') → 0'
half(s(0')) → 0'
half(s(s(x))) → s(half(x))
bits(0') → 0'
bits(s(x)) → s(bits(half(s(x))))
Types:
half :: 0':s → 0':s
0' :: 0':s
s :: 0':s → 0':s
bits :: 0':s → 0':s
hole_0':s1_0 :: 0':s
gen_0':s2_0 :: Nat → 0':s
(7) OrderProof (LOWER BOUND(ID) transformation)
Heuristically decided to analyse the following defined symbols:
half,
bitsThey will be analysed ascendingly in the following order:
half < bits
(8) Obligation:
TRS:
Rules:
half(
0') →
0'half(
s(
0')) →
0'half(
s(
s(
x))) →
s(
half(
x))
bits(
0') →
0'bits(
s(
x)) →
s(
bits(
half(
s(
x))))
Types:
half :: 0':s → 0':s
0' :: 0':s
s :: 0':s → 0':s
bits :: 0':s → 0':s
hole_0':s1_0 :: 0':s
gen_0':s2_0 :: Nat → 0':s
Generator Equations:
gen_0':s2_0(0) ⇔ 0'
gen_0':s2_0(+(x, 1)) ⇔ s(gen_0':s2_0(x))
The following defined symbols remain to be analysed:
half, bits
They will be analysed ascendingly in the following order:
half < bits
(9) RewriteLemmaProof (LOWER BOUND(ID) transformation)
Proved the following rewrite lemma:
half(
gen_0':s2_0(
*(
2,
n4_0))) →
gen_0':s2_0(
n4_0), rt ∈ Ω(1 + n4
0)
Induction Base:
half(gen_0':s2_0(*(2, 0))) →RΩ(1)
0'
Induction Step:
half(gen_0':s2_0(*(2, +(n4_0, 1)))) →RΩ(1)
s(half(gen_0':s2_0(*(2, n4_0)))) →IH
s(gen_0':s2_0(c5_0))
We have rt ∈ Ω(n1) and sz ∈ O(n). Thus, we have ircR ∈ Ω(n).
(10) Complex Obligation (BEST)
(11) Obligation:
TRS:
Rules:
half(
0') →
0'half(
s(
0')) →
0'half(
s(
s(
x))) →
s(
half(
x))
bits(
0') →
0'bits(
s(
x)) →
s(
bits(
half(
s(
x))))
Types:
half :: 0':s → 0':s
0' :: 0':s
s :: 0':s → 0':s
bits :: 0':s → 0':s
hole_0':s1_0 :: 0':s
gen_0':s2_0 :: Nat → 0':s
Lemmas:
half(gen_0':s2_0(*(2, n4_0))) → gen_0':s2_0(n4_0), rt ∈ Ω(1 + n40)
Generator Equations:
gen_0':s2_0(0) ⇔ 0'
gen_0':s2_0(+(x, 1)) ⇔ s(gen_0':s2_0(x))
The following defined symbols remain to be analysed:
bits
(12) NoRewriteLemmaProof (LOWER BOUND(ID) transformation)
Could not prove a rewrite lemma for the defined symbol bits.
(13) Obligation:
TRS:
Rules:
half(
0') →
0'half(
s(
0')) →
0'half(
s(
s(
x))) →
s(
half(
x))
bits(
0') →
0'bits(
s(
x)) →
s(
bits(
half(
s(
x))))
Types:
half :: 0':s → 0':s
0' :: 0':s
s :: 0':s → 0':s
bits :: 0':s → 0':s
hole_0':s1_0 :: 0':s
gen_0':s2_0 :: Nat → 0':s
Lemmas:
half(gen_0':s2_0(*(2, n4_0))) → gen_0':s2_0(n4_0), rt ∈ Ω(1 + n40)
Generator Equations:
gen_0':s2_0(0) ⇔ 0'
gen_0':s2_0(+(x, 1)) ⇔ s(gen_0':s2_0(x))
No more defined symbols left to analyse.
(14) LowerBoundsProof (EQUIVALENT transformation)
The lowerbound Ω(n1) was proven with the following lemma:
half(gen_0':s2_0(*(2, n4_0))) → gen_0':s2_0(n4_0), rt ∈ Ω(1 + n40)
(15) BOUNDS(n^1, INF)
(16) Obligation:
TRS:
Rules:
half(
0') →
0'half(
s(
0')) →
0'half(
s(
s(
x))) →
s(
half(
x))
bits(
0') →
0'bits(
s(
x)) →
s(
bits(
half(
s(
x))))
Types:
half :: 0':s → 0':s
0' :: 0':s
s :: 0':s → 0':s
bits :: 0':s → 0':s
hole_0':s1_0 :: 0':s
gen_0':s2_0 :: Nat → 0':s
Lemmas:
half(gen_0':s2_0(*(2, n4_0))) → gen_0':s2_0(n4_0), rt ∈ Ω(1 + n40)
Generator Equations:
gen_0':s2_0(0) ⇔ 0'
gen_0':s2_0(+(x, 1)) ⇔ s(gen_0':s2_0(x))
No more defined symbols left to analyse.
(17) LowerBoundsProof (EQUIVALENT transformation)
The lowerbound Ω(n1) was proven with the following lemma:
half(gen_0':s2_0(*(2, n4_0))) → gen_0':s2_0(n4_0), rt ∈ Ω(1 + n40)
(18) BOUNDS(n^1, INF)