(0) Obligation:

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

sel(s(X), cons(Y, Z)) → sel(X, Z)
sel(0, cons(X, Z)) → X
first(0, Z) → nil
first(s(X), cons(Y, Z)) → cons(Y, first(X, Z))
from(X) → cons(X, from(s(X)))
sel1(s(X), cons(Y, Z)) → sel1(X, Z)
sel1(0, cons(X, Z)) → quote(X)
first1(0, Z) → nil1
first1(s(X), cons(Y, Z)) → cons1(quote(Y), first1(X, Z))
quote(0) → 01
quote1(cons(X, Z)) → cons1(quote(X), quote1(Z))
quote1(nil) → nil1
quote(s(X)) → s1(quote(X))
quote(sel(X, Z)) → sel1(X, Z)
quote1(first(X, Z)) → first1(X, Z)
unquote(01) → 0
unquote(s1(X)) → s(unquote(X))
unquote1(nil1) → nil
unquote1(cons1(X, Z)) → fcons(unquote(X), unquote1(Z))
fcons(X, Z) → cons(X, Z)

Rewrite Strategy: FULL

(1) InfiniteLowerBoundProof (EQUIVALENT transformation)

The loop following loop proves infinite runtime complexity:
The rewrite sequence
from(X) →+ cons(X, from(s(X)))
gives rise to a decreasing loop by considering the right hand sides subterm at position [1].
The pumping substitution is [ ].
The result substitution is [X / s(X)].