I am not a mathematician, but rather a computer engineer with a curious mind.
The continuum hypothesis (CH) has gripped my attention today, and I even asked a question about it earlier today. However, I seem to be unable to grasp the ideas correctly because I've reached a conclusion that I'm sure is wrong but I don't understand why it's wrong.
EDIT: adding the CH for clarification of what I'm trying to prove
Continuum Hypothesis: There does not exist a set $S$ such that $\aleph_0 < |S| < 2^{\aleph_0}$
Something that I learned from my last question: $n^{\aleph_0}$ can be interpreted as the cardinality of the set constructed by enumerating all of the possible sequences of choosing between $n$ choices $\aleph_0$ number of times.
EDIT: It nags me that the continuum theorem is still unproven after over 100 years, so I played with some ideas on paper to hopefully hit a brick wall and understand why the CH is so difficult to prove. I didn't hit a brick wall, but rather I seem to have run off of a cliff and was hoping for some guidance (or maybe a parachute in this metaphor).
I defined a function which describes the cardinality of a set as follows
$J(c+\frac{m}{n}, d \times n) : m < n ; c,d,m,n \in \mathbb{N}$ is the cardinality of the set constructed by choosing between $c$ choices $n-m$ number of times, then between $c+1$ choices $m$ times, repeated $d$ number of times.
Examples:
- $J(1.5, 4) = J(1 + \frac{1}{2}, 2 \times 2) = (1 \times 2) \times (1 \times 2) = 4$
- $J(2, 7) = J(2 + \frac{0}{1}, 7 \times 1) = (2) \times (2) \times (2) \times (2) \times (2) \times (2) \times (2) = 128$
- $J(2.2, 10) = J(2 + \frac{1}{5}, 2 \times 5) = (2 \times 2 \times 2 \times 2 \times 3) \times (2 \times 2 \times 2 \times 2 \times 3) = 2304$
- $J(3.25, 8) = J(3 + \frac{1}{4}, 2 \times 4) = (3 \times 3 \times 3 \times 4) \times (3 \times 3 \times 3 \times 4) = 11664$
I think some things are clear, but please correct me if one or more of these assertions are wrong.
- $J(s_0,t) \leq J(s_1,t) \leftrightarrow s_0 \leq s_1$
- $J(s,t_0) \leq J(s,t_1) \leftrightarrow t_0 \leq t_1$
- $J(n, m) = n^{m} : n,m \in \mathbb{N}$
- $J(n, \aleph_0) = n^{\aleph_0}$ by the interpretation of $n^{\aleph_0}$ that I stated earlier in the problem.
I also think that it's clear that $J(1+q, \aleph_0) = 2^{\aleph_0}$ $\forall$ $0 < q < 1, q \in \mathbb{Q}$. I wrote a small proof on my notepad around the idea that finite $q$ will yield a finite $t$ where $(1+q)^t \geq 2$. Correct me if I'm making a mistake here.
Now, for every $\epsilon > 0$, there exists a $q < \epsilon$, $q \in \mathbb{Q}$. Now I plot the function $f(x) = J(x, \aleph_0)$ over the range of say $[1,2]$, $f(x)$ jumps from $1$ to $2^{\aleph_0}$ and right over $\aleph_0$! What's going on here?
More info:
My original try was in a different wording of $J(s,t)$: "... repeated 1 through $d$ number of times. This made $f(x)$ jump from $\aleph_0$ to $2^{\aleph_0}$ between $x=1$ and $x=1 + \epsilon$ for any $\epsilon > 0$. This made me excited until I realized that a different definition of $J(s,t)$ skipped over $\aleph_0$ entirely.
I admit, I was assuming that the CH was true and this basically moved me in the direction of trying to prove that it was true but somewhere I have made an assumption that's false. I was attempting to create a function $J(s,t)$ that resembled the cardinal exponential function $s^t$ in an attempt to get a continuous function over a range to prove that there are no cardinalities between $\aleph_0$ and $2^{\aleph_0}$. This approach seems fundamentally flawed (because one of my definitions "proved" that $\aleph_0$ didn't exist!). Can someone explain the flaw to me?
The biggest issue here is the following misconception: $$\huge\textbf{Cardinals are not real numbers!}$$
The fact that for finite cardinals the basic arithmetic coincides with that of the natural numbers and thus with the reals does not grant you the same toolkit with cardinals in general. Even less so when limits are considered.
So either you define a function on the rational numbers which gives back cardinals, which is fine, but then $\aleph_0$ is not a rational number and you cannot put it into the domain of the function, or you defined a function from cardinals to cardinals but then you have no business feeding it rational numbers. There is no set whose cardinality is a fraction.
One of the factors to this confusion is an ill equipped toolkit. The infinity dealt with as far as real analysis goes is absolutely unrelated to cardinal numbers and requires a different kind of machinery to work. Things become even more troublesome if you throw ordinal arithmetic into the pot, which is also very different.
In short, as was mentioned in the comments, there is no reason to expect that cardinal exponentiation is continuous at limits. But the problems begin on a deeper level, as written in large, boldface letters in the beginning of my answer.