Thank you for the response.
You are right about the "need for speciation". Let me correct: Since different extant species have different address spaces, the address space has to change during the course of evolution.
What I am trying to understand is whether this change is "qualitatively" any different from the change in genetic content. As I understand, your answer is "no", which I am willing to admit. But I believe it is a good exercise (at least for me) on understanding evolution, so I will continue.
Theoretically, the difference between "changing a vector's value in one dimension" is qualitatively different from "adding a new dimension" to the vector. Therefore, although it is apparently true from a biological perspective that there is no qualitative difference between a gene duplication and point mutation in terms of effecting reproductivity, there must at least be a "sharp" quantitative difference. In other words, we cannot expect the gene pool of a particular species to fluctuate significantly in terms of its "genetic address space" (at least, I would guess this is what we observe).
Therefore, it appears to me that the distinction between "genetic address space" and "genetic content" should have something to do with speciation, or find some place in the molecular bases for "punctuated equilibrium". Sorry, I am not fully informed about population genetics, so I might be mentioning something obvious here. Still, I will appreciate if anybody could let me know whether there is any literature that could relate to this "address space" abstraction. Or should I just go ahead and read specifically about gene duplication, chromosome reorganization, etc.?