pzkpfw
Registered Member
you
"But the method is applied to an infinite series from M: the series E1, E2, …, Ev, it's not applied to M."
Cantor
"Namely, let m and n be two different characters, and consider a set [Inbegriff] M of elements
E = (x1, x2, … , xv, …)
which depend on infinitely many coordinates x1, x2, … , xv, …, and where each of the coordinates is either m or w."
[He clearly defines the set M composed of sequences En, each composed of coordinates xn, each m or w.
The same exclusion of E0 from M would occur for subsets.
It is plainly obvious that if something isn't in M it cannot be in a subset of M.
But that isn't what Cantors' method is about.
** if you think it is, that's what you need to try to show. Focus! **
Two different orientations cannot coexist in the same list.]
And again with the "different orientations". The diagonal is just a way to [ find / see / look for / choose / select ] characters to make a new element with. That new element is a valid member of M, as M is defined as "all". The question is whether it's a member of the given list (subset).
you
"Cantor then asks if all of M is in E1, E2, …, Ev - by seeing if he can make an E0 (which would be in M as M is all) that clearly isn't in E1, E2, …, Ev."
[He defines the diagonal symbols as a qualified sequence D without knowing if it is a duplicate. He already knows his E0 will differ from D after exchanging symbols which doesn't allow both to coexist in the same list. His action produces the exclusion.
It doesn't matter if D is a duplicate (of what?). It must be a member of M. It might be a member of the subset.
The method isn't about whether D and E0 "coexist" in the same subset (or M).
The point is that E0 cannot be in the subset - because it's different to E1 at character 1, etc.
Given, a pixel display screen with only 8 basic colors,
a green diagonal line from (x=0, y=0) and
a red horizontal line from (x=0, y=10).
What color is the pixel at the intersection of (10, 10) without mixing?
Completely and totally irrelevant. Again, he's not putting two things in one place.
The diagonal isn't there to put a new thing at any coordinate.
The diagonal is just to [ find / see / look for / choose / select ] characters to make a new element with.
The equivalent, using your "pixel display screen with only 8 basic colours" would be more like:
Given "a red horizontal line from (x=0, y=10)."
We create D with red at X=10
So we get E0 with cyan at X=10
So we know E0 cannot be a row on that screen (because of that and its other pixels)
Nobody is putting two things in one place.
He interprets exclusion of E0 as a missing E0.]
Yes, E0 is "missing" from the subset. E0 cannot be any of the elements in the subset, because it's different to all of them by at least one character.
(E0 will be in M.)
you
"3: Finally: this means there are infinite sequences in your binary tree, that are not in the infinite sequence starting at M0. Agree?"
[I have revised the tree for more clarity. M contains all possible sequences.
Cantor can say E0=0101... is in M if he is looking at subset M0 and
not in M if he is looking at subset M1. That is not a contradiction.]
It almost sounds like you've got it here!
you
"Cantor would be happy that a sequence starting with 1 is not in the list of infinite sequences starting with 0."
[He was developing set theory in the form of transfinite sets, thus he would already know the definition of subsets.]
View attachment 7599
Yes!
If the diagonal on some subset of sequences from the tree was the D you highlight in red above, then the resulting E0 would be what you highlight in red.
But - as you show, your tree represents M. Your tree does not represent a subset of M.
We all know D and E0 (and any Ex) are in your tree (M).
The question is whether E0 would be in a subset of your tree (M).
Consider:
1. Pick any infinite subset of your tree, e.g. all the sequences starting 01..., 10..., and 11...
2. Pick any characters from 1. to be D. Don't care how you choose D; flip coins or whatever. All that matters is you take the 1st from one sequence, the 2nd from another, and so on.
3. Generate E by flipping the characters of D.
4. E is obviously in the full tree (M), but is it in the subset you made in step 1?
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