(0) Obligation:

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

rev(nil) → nil
rev(cons(x, l)) → cons(rev1(x, l), rev2(x, l))
rev1(0, nil) → 0
rev1(s(x), nil) → s(x)
rev1(x, cons(y, l)) → rev1(y, l)
rev2(x, nil) → nil
rev2(x, cons(y, l)) → rev(cons(x, rev2(y, l)))

Rewrite Strategy: FULL

(1) DecreasingLoopProof (EQUIVALENT transformation)

The following loop(s) give(s) rise to the lower bound Ω(2n):
The rewrite sequence
rev2(x, cons(y, l)) →+ cons(rev1(x, rev2(y, l)), rev2(x, rev2(y, l)))
gives rise to a decreasing loop by considering the right hand sides subterm at position [0,1].
The pumping substitution is [l / cons(y, l)].
The result substitution is [x / y].

The rewrite sequence
rev2(x, cons(y, l)) →+ cons(rev1(x, rev2(y, l)), rev2(x, rev2(y, l)))
gives rise to a decreasing loop by considering the right hand sides subterm at position [1,1].
The pumping substitution is [l / cons(y, l)].
The result substitution is [x / y].

(2) BOUNDS(2^n, INF)