Solution:
Use the same notation as in solution 1. We wish to construct a partition ⋃i∈Z+Ai of the positive integers, such that no two sets among all sets in {dA1}n∈Z+,{dA2}n∈Z+,… are equal.
To begin with, consider a partition ⋃i∈Z+Pi of the primes, such that each Pi={pi1,pi2,…} is infinite. We may assume each set is infinite since the set of primes and Z+×Z+ both are countable, so there exists a bijection between them. Define the sets
Qi={pi1,pi22,pi3,pi33,pi42,pi44,pi5,pi53,pi55,…}
consisting of pijj,pijj−2,…,pij(1,2) for each pij∈Pi. By the exponent (1,2) we indicate that the last power is 1 when j is odd and 2 when it is even.
We will include the remaining integers {r1,r2,…}=Z+\(⋃i∈Z+Qi) to the partition as follows. First, add r1 to some set Qi1, such that gcd(r1,q)=1 for each q∈Qi1. Then, for each k∈Z+, add rk+1 to a set Qik+1 where ik+1>ik, such that gcd(rk+1,q)=1 for each q∈Qik+1. Note that such an ik+1 always exists, since there always is an infinite amount of prime divisors among Qik+1,Qik+2,…, and rk+1 only has a finite amount of prime divisors.
The collection of Qi now forms a partition of Z+. What remains is to show that it satisfies Alice's winning condition.
We first see that we may ignore all the rk. By definition, no divisor of rk coincides with any divisor of Qik, and their contributions in the d-sequence will therefore be completely disjoint. As d(d({rk}))=∅, the d-sequence will show no trace of the rk after the second element. Hence, we will work with the original Qi.
We observe that d(Qi)={1,pi2,pi32,pi4,pi43,pi52,pi54,pi6,pi63,pi65,…}. This is simply Qi with the indices shifted by 1 and with an added 1. As this set essentially is on the same form as Qi, we see that {dQi}n consists of every possible shift in indices of the first set Qi (except the element 1 appearing in every other set). It is therefore obvious that the sets in the sequence are pairwise distinct. Additionally, the set of primes dividing some element in some set of {dQi}n is Pi. Since the Pi partition the primes, it is clear that all the sets in all the d-sequences of the Qi are distinct, which is what we wanted.
Remark. The main idea of the problem is to construct a single set S, such that the sets in the d-sequence of S are pairwise distinct. Any set with similar properties to the Qi should give a valid initial collection C such that Alice wins.