(0) Obligation:
Runtime Complexity TRS:
The TRS R consists of the following rules:
half(x) → if(ge(x, s(s(0))), x)
if(false, x) → 0
if(true, x) → s(half(p(p(x))))
p(0) → 0
p(s(x)) → x
ge(x, 0) → true
ge(0, s(x)) → false
ge(s(x), s(y)) → ge(x, y)
log(0) → 0
log(s(x)) → s(log(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(x97_1))) →+ s(half(x97_1))
gives rise to a decreasing loop by considering the right hand sides subterm at position [0].
The pumping substitution is [x97_1 / s(s(x97_1))].
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(x) → if(ge(x, s(s(0'))), x)
if(false, x) → 0'
if(true, x) → s(half(p(p(x))))
p(0') → 0'
p(s(x)) → x
ge(x, 0') → true
ge(0', s(x)) → false
ge(s(x), s(y)) → ge(x, y)
log(0') → 0'
log(s(x)) → s(log(half(s(x))))
S is empty.
Rewrite Strategy: FULL
(5) TypeInferenceProof (BOTH BOUNDS(ID, ID) transformation)
Infered types.
(6) Obligation:
TRS:
Rules:
half(x) → if(ge(x, s(s(0'))), x)
if(false, x) → 0'
if(true, x) → s(half(p(p(x))))
p(0') → 0'
p(s(x)) → x
ge(x, 0') → true
ge(0', s(x)) → false
ge(s(x), s(y)) → ge(x, y)
log(0') → 0'
log(s(x)) → s(log(half(s(x))))
Types:
half :: 0':s → 0':s
if :: false:true → 0':s → 0':s
ge :: 0':s → 0':s → false:true
s :: 0':s → 0':s
0' :: 0':s
false :: false:true
true :: false:true
p :: 0':s → 0':s
log :: 0':s → 0':s
hole_0':s1_0 :: 0':s
hole_false:true2_0 :: false:true
gen_0':s3_0 :: Nat → 0':s
(7) OrderProof (LOWER BOUND(ID) transformation)
Heuristically decided to analyse the following defined symbols:
half,
ge,
logThey will be analysed ascendingly in the following order:
ge < half
half < log
(8) Obligation:
TRS:
Rules:
half(
x) →
if(
ge(
x,
s(
s(
0'))),
x)
if(
false,
x) →
0'if(
true,
x) →
s(
half(
p(
p(
x))))
p(
0') →
0'p(
s(
x)) →
xge(
x,
0') →
truege(
0',
s(
x)) →
falsege(
s(
x),
s(
y)) →
ge(
x,
y)
log(
0') →
0'log(
s(
x)) →
s(
log(
half(
s(
x))))
Types:
half :: 0':s → 0':s
if :: false:true → 0':s → 0':s
ge :: 0':s → 0':s → false:true
s :: 0':s → 0':s
0' :: 0':s
false :: false:true
true :: false:true
p :: 0':s → 0':s
log :: 0':s → 0':s
hole_0':s1_0 :: 0':s
hole_false:true2_0 :: false:true
gen_0':s3_0 :: Nat → 0':s
Generator Equations:
gen_0':s3_0(0) ⇔ 0'
gen_0':s3_0(+(x, 1)) ⇔ s(gen_0':s3_0(x))
The following defined symbols remain to be analysed:
ge, half, log
They will be analysed ascendingly in the following order:
ge < half
half < log
(9) RewriteLemmaProof (LOWER BOUND(ID) transformation)
Proved the following rewrite lemma:
ge(
gen_0':s3_0(
n5_0),
gen_0':s3_0(
n5_0)) →
true, rt ∈ Ω(1 + n5
0)
Induction Base:
ge(gen_0':s3_0(0), gen_0':s3_0(0)) →RΩ(1)
true
Induction Step:
ge(gen_0':s3_0(+(n5_0, 1)), gen_0':s3_0(+(n5_0, 1))) →RΩ(1)
ge(gen_0':s3_0(n5_0), gen_0':s3_0(n5_0)) →IH
true
We have rt ∈ Ω(n1) and sz ∈ O(n). Thus, we have ircR ∈ Ω(n).
(10) Complex Obligation (BEST)
(11) Obligation:
TRS:
Rules:
half(
x) →
if(
ge(
x,
s(
s(
0'))),
x)
if(
false,
x) →
0'if(
true,
x) →
s(
half(
p(
p(
x))))
p(
0') →
0'p(
s(
x)) →
xge(
x,
0') →
truege(
0',
s(
x)) →
falsege(
s(
x),
s(
y)) →
ge(
x,
y)
log(
0') →
0'log(
s(
x)) →
s(
log(
half(
s(
x))))
Types:
half :: 0':s → 0':s
if :: false:true → 0':s → 0':s
ge :: 0':s → 0':s → false:true
s :: 0':s → 0':s
0' :: 0':s
false :: false:true
true :: false:true
p :: 0':s → 0':s
log :: 0':s → 0':s
hole_0':s1_0 :: 0':s
hole_false:true2_0 :: false:true
gen_0':s3_0 :: Nat → 0':s
Lemmas:
ge(gen_0':s3_0(n5_0), gen_0':s3_0(n5_0)) → true, rt ∈ Ω(1 + n50)
Generator Equations:
gen_0':s3_0(0) ⇔ 0'
gen_0':s3_0(+(x, 1)) ⇔ s(gen_0':s3_0(x))
The following defined symbols remain to be analysed:
half, log
They will be analysed ascendingly in the following order:
half < log
(12) NoRewriteLemmaProof (LOWER BOUND(ID) transformation)
Could not prove a rewrite lemma for the defined symbol half.
(13) Obligation:
TRS:
Rules:
half(
x) →
if(
ge(
x,
s(
s(
0'))),
x)
if(
false,
x) →
0'if(
true,
x) →
s(
half(
p(
p(
x))))
p(
0') →
0'p(
s(
x)) →
xge(
x,
0') →
truege(
0',
s(
x)) →
falsege(
s(
x),
s(
y)) →
ge(
x,
y)
log(
0') →
0'log(
s(
x)) →
s(
log(
half(
s(
x))))
Types:
half :: 0':s → 0':s
if :: false:true → 0':s → 0':s
ge :: 0':s → 0':s → false:true
s :: 0':s → 0':s
0' :: 0':s
false :: false:true
true :: false:true
p :: 0':s → 0':s
log :: 0':s → 0':s
hole_0':s1_0 :: 0':s
hole_false:true2_0 :: false:true
gen_0':s3_0 :: Nat → 0':s
Lemmas:
ge(gen_0':s3_0(n5_0), gen_0':s3_0(n5_0)) → true, rt ∈ Ω(1 + n50)
Generator Equations:
gen_0':s3_0(0) ⇔ 0'
gen_0':s3_0(+(x, 1)) ⇔ s(gen_0':s3_0(x))
The following defined symbols remain to be analysed:
log
(14) NoRewriteLemmaProof (LOWER BOUND(ID) transformation)
Could not prove a rewrite lemma for the defined symbol log.
(15) Obligation:
TRS:
Rules:
half(
x) →
if(
ge(
x,
s(
s(
0'))),
x)
if(
false,
x) →
0'if(
true,
x) →
s(
half(
p(
p(
x))))
p(
0') →
0'p(
s(
x)) →
xge(
x,
0') →
truege(
0',
s(
x)) →
falsege(
s(
x),
s(
y)) →
ge(
x,
y)
log(
0') →
0'log(
s(
x)) →
s(
log(
half(
s(
x))))
Types:
half :: 0':s → 0':s
if :: false:true → 0':s → 0':s
ge :: 0':s → 0':s → false:true
s :: 0':s → 0':s
0' :: 0':s
false :: false:true
true :: false:true
p :: 0':s → 0':s
log :: 0':s → 0':s
hole_0':s1_0 :: 0':s
hole_false:true2_0 :: false:true
gen_0':s3_0 :: Nat → 0':s
Lemmas:
ge(gen_0':s3_0(n5_0), gen_0':s3_0(n5_0)) → true, rt ∈ Ω(1 + n50)
Generator Equations:
gen_0':s3_0(0) ⇔ 0'
gen_0':s3_0(+(x, 1)) ⇔ s(gen_0':s3_0(x))
No more defined symbols left to analyse.
(16) LowerBoundsProof (EQUIVALENT transformation)
The lowerbound Ω(n1) was proven with the following lemma:
ge(gen_0':s3_0(n5_0), gen_0':s3_0(n5_0)) → true, rt ∈ Ω(1 + n50)
(17) BOUNDS(n^1, INF)
(18) Obligation:
TRS:
Rules:
half(
x) →
if(
ge(
x,
s(
s(
0'))),
x)
if(
false,
x) →
0'if(
true,
x) →
s(
half(
p(
p(
x))))
p(
0') →
0'p(
s(
x)) →
xge(
x,
0') →
truege(
0',
s(
x)) →
falsege(
s(
x),
s(
y)) →
ge(
x,
y)
log(
0') →
0'log(
s(
x)) →
s(
log(
half(
s(
x))))
Types:
half :: 0':s → 0':s
if :: false:true → 0':s → 0':s
ge :: 0':s → 0':s → false:true
s :: 0':s → 0':s
0' :: 0':s
false :: false:true
true :: false:true
p :: 0':s → 0':s
log :: 0':s → 0':s
hole_0':s1_0 :: 0':s
hole_false:true2_0 :: false:true
gen_0':s3_0 :: Nat → 0':s
Lemmas:
ge(gen_0':s3_0(n5_0), gen_0':s3_0(n5_0)) → true, rt ∈ Ω(1 + n50)
Generator Equations:
gen_0':s3_0(0) ⇔ 0'
gen_0':s3_0(+(x, 1)) ⇔ s(gen_0':s3_0(x))
No more defined symbols left to analyse.
(19) LowerBoundsProof (EQUIVALENT transformation)
The lowerbound Ω(n1) was proven with the following lemma:
ge(gen_0':s3_0(n5_0), gen_0':s3_0(n5_0)) → true, rt ∈ Ω(1 + n50)
(20) BOUNDS(n^1, INF)