Comments by "B" (@user-pr6ed3ri2k) on "How An Infinite Hotel Ran Out Of Room" video.
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@robotnoir5299 @robot noir new1stpara: ok, are numbers a physical thing in reality? no wait don't answer that, philosophy sucks
new2ndpart: idk
new3rdpart: um, there is a correct answer, and that answer was made from the zfc axioms + endlessness is a possible concept. if it wasn't, why would we even have a word for it?
to last part: uh, the hotel is just an analogy, it's just supposed to be a intuitive way to understand cardinality assuming that everything is idealized, and there are no karens, and they can switch rooms in precisely 0 seconds, and that no one destroys the whole place, etc.
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@robotnoir5299 also, the axioms were designed to be as reasonable as possible. I can list them here in oversimplified form:
1. 2 sets are equal iff (if and only if) they have the same elements (axiom of extensionality)
2. a set doesn't have infinite nested sets. (axiom of foundation)
3. set builder only used to define a certain subset of a set. if you don't have this, you'll get that weird error when you make the set of all sets that don't contain themselves and the set of everything. (axiom schema of restricted comprehension)(axiom 2 also prevents paradoxes)(schema because set builder can have many different predicates an inputs)
4. if you have 2 sets, x and y, the set that contains both x and y exists. (axiom of pairing)
5. the set you get from grouping all the members of the members of a set (this set has only sets as members and those sets have sets)(basically a nested set) exists. (axiom of union)
6. the set of all outputs of a function f(x) that you can define exists. (axiom schema of replacement)(schema because there are many different kinds of f(x) (obviously))
7. there exists a set X with infinitely many unique members (example: {1, 2, 3, ...}) (axiom of infinity)
8. the powerset of a set exists. (take a set, make a set of all sets that are like the original set except missing or not missing some of the elements)(the party bus in the video is equivalent to the numbers between zero and 1 in size which is equivalent to the powerset of naturals (the room numbers; {1, 2, 3, ...}) in size. ) (axiom of powerset)
thats standard 8 in zf
zfc has a ninth one
9. for all sets R, there is some binary relation X (like a < x, only compares 2 elements) that well-orders R. (well-ordering theorem)
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@fall4sleepfall4sleep26 uh, there is no such thing as a start and end to infinity, it's a concept, not a mathematical object
also, one is bigger, powerset aleph null is bigger, and i have proof of that
lets say you have powerset n0 and n0 in a list:
N_0 2^N_0
1 AABAAABABBBABA...
2 BABBAAABABABAB...
3 BBAAABABABAAAB...
4 BABABABAAAABAB...
5 AAAABAAAABAAAA...
... ...
of course, it doesn't matter how 2^N_0 is
ordered because you can't list it out.
next, get the first letter of the first word, 2nd of the 2nd word, third of the third word, and so on, and make a new word that has all those letters in the same place but flipped, then boom, you have even more words in 2^N_0 than N_0.
tell me, how can you say that N_0 is bigger than 2^N_0?
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@clurtzy uhm, haven't you considered the possibility that you don't understand?
ok, i'll try my best to decipher your comment. infinite amount of names with no end? yeah, i get that. oh, so your point is all names are taken up? well, the way we make the new name is by making the 1st letter different from the first name's first letter, the 2nd is different from the 2nd of the 2nd name, and so on, so technically, by definition, you are wrong.
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@robotnoir5299 um, you cant prove that, and by occams razor or whatever, simplest explanation holds + to 2nd part, the youtube censor isnt intelligent, it does not care about if the comment was good or not, it just cares if it was inappropriate, which in this case, it isnt, because there are tons of r/badmathematics (yes i do use reddit) content on youtube that havent been deleted yet, so clearly, this filter that apparently deletes crank content doesnt seem to work
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@fall4sleepfall4sleep26 i choose the reals, and i will now prove why the reals are more numerous. lets first state that the size of the naturals is a cardinal number, called aleph 0, or N_0 for short. next, try to show a 1 to 1 correspondence with the naturals (N_0) and the reals between 0 and 1.
1. 0.92848287373727...
2. 0.838274991873848...
3. 0.848479292841910...
4. 0.928391938488288...
5. 0.828478283838828...
...
I can order the reals between 0 and 1 any way i like, because there is no way to find the next number in the reals.
next, take the first digit of the first number, which is in this case 9,and add 1 unless it's 9, which it is, so subtract 1, and make a new decimal starting with that number (0.8). next, get the 2nd of the 2nd number (3) and add 1 and put it in the new string of numbers. (0.83)
repeat. (0.83948...). there we go, a new number that's guaranteed to be different to ALL the numbers on the list, because we defined it to be different. as you can see, I just proved that the numbers 0<number<1 is bigger than the naturals. next, lets prove all of the reals. first notice that the reals will be the exact same form as the numbers between 0 and 1, except you put a natural at the start. (after all, the numbers between 0 and 1 are all the decimals possible, all numbers of the form 0.something) since the size of the naturals is N_0 by definition, we can multiply N_0 and the size of the numbers between 0 and 1, and by the rules of cardinal math, big infinity will absorb small infinity, and since i just proved that (size of numbers between 0 and 1) > (size of your set, the naturals), i have just proven that the size of the set R, the reals, is bigger than the size of N, the naturals.
any complaints?
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