Your speaking in two languages at once, a mathematical language of finite numbers. And at the same time using a language consisting of words that are not mathematical.
Infinity is not a numerical entity.
A set of any finite numbers is never an infinite set, because the term 'infinite' is not numerically defined.
I will prove this now.
Consider the set of positive integers, {1,2,3,...}
This set of positive integers contains only positive integers.
Since every single positive integer in that set is always followed by another positive integer. Then that set is by definition is bounded by the finite set of all numbers.
If you were to say, a finite set can be an infinite set. Then that is a paradox.
Mathematics is a discipline concerned with numbers and infinity is not a number.
Your trying to claim that some set of finite numbers, is somehow, an infinite set of finite numbers?
Why don't you pay attention to essentialsaltes' posts instead of making things up.
An infinite set contains an infinite number of elements.
The set of natural numbers N = {0,1,2,3…………….} is clearly an infinite set as is the set of integers Z = {…….-3,-2,-1, 0,1,2,3……….}
An infinite set that is countable means that each element in the set can be mapped from the set of natural numbers by a one-one and onto function.
For example the infinite set of integers Z is countable according to the function f;
f(n) = n/2 where n is even or zero and f(n) = -(n-1)/2 if n is odd; n is an element of N.
There are some very surprising results.
The infinite set of rational numbers Q is countable as a function f can be defined.
The infinite set of real numbers R on the other hand is an uncountable infinite set as no such function f can exist.
The set of prime numbers is an infinite set.
This was proven by the ancient Greeks who used proof by contradiction method where they assumed the set of prime numbers formed a finite set with the largest prime number.
What they found was there always a larger prime number outside this set irrespective of how large they made the finite set.
Hence by contradiction the set of prime numbers is an infinite set.