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

(0) Obligation:

Runtime Complexity TRS:
The TRS R consists of the following rules:

g(s(x)) → f(x)
f(0) → s(0)
f(s(x)) → s(s(g(x)))
g(0) → 0

Rewrite Strategy: INNERMOST

(1) RenamingProof (EQUIVALENT transformation)

Renamed function symbols to avoid clashes with predefined symbol.

(2) Obligation:

Runtime Complexity Relative TRS:
The TRS R consists of the following rules:

g(s(x)) → f(x)
f(0') → s(0')
f(s(x)) → s(s(g(x)))
g(0') → 0'

S is empty.
Rewrite Strategy: INNERMOST

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

Infered types.

(4) Obligation:

Innermost TRS:
Rules:
g(s(x)) → f(x)
f(0') → s(0')
f(s(x)) → s(s(g(x)))
g(0') → 0'

Types:
g :: s:0' → s:0'
s :: s:0' → s:0'
f :: s:0' → s:0'
0' :: s:0'
hole_s:0'1_0 :: s:0'
gen_s:0'2_0 :: Nat → s:0'

(5) OrderProof (LOWER BOUND(ID) transformation)

Heuristically decided to analyse the following defined symbols:
g, f

They will be analysed ascendingly in the following order:
g = f

(6) Obligation:

Innermost TRS:
Rules:
g(s(x)) → f(x)
f(0') → s(0')
f(s(x)) → s(s(g(x)))
g(0') → 0'

Types:
g :: s:0' → s:0'
s :: s:0' → s:0'
f :: s:0' → s:0'
0' :: s:0'
hole_s:0'1_0 :: s:0'
gen_s:0'2_0 :: Nat → s:0'

Generator Equations:
gen_s:0'2_0(0) ⇔ 0'
gen_s:0'2_0(+(x, 1)) ⇔ s(gen_s:0'2_0(x))

The following defined symbols remain to be analysed:
f, g

They will be analysed ascendingly in the following order:
g = f

(7) RewriteLemmaProof (LOWER BOUND(ID) transformation)

Proved the following rewrite lemma:
f(gen_s:0'2_0(*(2, n4_0))) → gen_s:0'2_0(+(1, *(2, n4_0))), rt ∈ Ω(1 + n4₀)

Induction Base:
f(gen_s:0'2_0(*(2, 0))) →_R^Ω(1)
s(0')

Induction Step:
f(gen_s:0'2_0(*(2, +(n4_0, 1)))) →_R^Ω(1)
s(s(g(gen_s:0'2_0(+(1, *(2, n4_0)))))) →_R^Ω(1)
s(s(f(gen_s:0'2_0(*(2, n4_0))))) →_IH
s(s(gen_s:0'2_0(+(1, *(2, c5_0)))))

We have rt ∈ Ω(n¹) and sz ∈ O(n). Thus, we have irc_R ∈ Ω(n).

(8) Complex Obligation (BEST)

(9) Obligation:

Innermost TRS:
Rules:
g(s(x)) → f(x)
f(0') → s(0')
f(s(x)) → s(s(g(x)))
g(0') → 0'

Types:
g :: s:0' → s:0'
s :: s:0' → s:0'
f :: s:0' → s:0'
0' :: s:0'
hole_s:0'1_0 :: s:0'
gen_s:0'2_0 :: Nat → s:0'

Lemmas:
f(gen_s:0'2_0(*(2, n4_0))) → gen_s:0'2_0(+(1, *(2, n4_0))), rt ∈ Ω(1 + n4₀)

Generator Equations:
gen_s:0'2_0(0) ⇔ 0'
gen_s:0'2_0(+(x, 1)) ⇔ s(gen_s:0'2_0(x))

The following defined symbols remain to be analysed:
g

They will be analysed ascendingly in the following order:
g = f

(10) NoRewriteLemmaProof (LOWER BOUND(ID) transformation)

Could not prove a rewrite lemma for the defined symbol g.

(11) Obligation:

Innermost TRS:
Rules:
g(s(x)) → f(x)
f(0') → s(0')
f(s(x)) → s(s(g(x)))
g(0') → 0'

Types:
g :: s:0' → s:0'
s :: s:0' → s:0'
f :: s:0' → s:0'
0' :: s:0'
hole_s:0'1_0 :: s:0'
gen_s:0'2_0 :: Nat → s:0'

Lemmas:
f(gen_s:0'2_0(*(2, n4_0))) → gen_s:0'2_0(+(1, *(2, n4_0))), rt ∈ Ω(1 + n4₀)

Generator Equations:
gen_s:0'2_0(0) ⇔ 0'
gen_s:0'2_0(+(x, 1)) ⇔ s(gen_s:0'2_0(x))

No more defined symbols left to analyse.

(12) LowerBoundsProof (EQUIVALENT transformation)

The lowerbound Ω(n¹) was proven with the following lemma:
f(gen_s:0'2_0(*(2, n4_0))) → gen_s:0'2_0(+(1, *(2, n4_0))), rt ∈ Ω(1 + n4₀)

(13) BOUNDS(n^1, INF)

(14) Obligation:

Innermost TRS:
Rules:
g(s(x)) → f(x)
f(0') → s(0')
f(s(x)) → s(s(g(x)))
g(0') → 0'

Types:
g :: s:0' → s:0'
s :: s:0' → s:0'
f :: s:0' → s:0'
0' :: s:0'
hole_s:0'1_0 :: s:0'
gen_s:0'2_0 :: Nat → s:0'

Lemmas:
f(gen_s:0'2_0(*(2, n4_0))) → gen_s:0'2_0(+(1, *(2, n4_0))), rt ∈ Ω(1 + n4₀)

Generator Equations:
gen_s:0'2_0(0) ⇔ 0'
gen_s:0'2_0(+(x, 1)) ⇔ s(gen_s:0'2_0(x))

No more defined symbols left to analyse.

(15) LowerBoundsProof (EQUIVALENT transformation)

The lowerbound Ω(n¹) was proven with the following lemma:
f(gen_s:0'2_0(*(2, n4_0))) → gen_s:0'2_0(+(1, *(2, n4_0))), rt ∈ Ω(1 + n4₀)

(16) BOUNDS(n^1, INF)