- #36
matt grime
Science Advisor
Homework Helper
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Ok, I'm beginning to see the picture.
1. The binary tree is what i said it is - the infinite thing above. At the k'th level you number the nodes from 1 to 2^k using binary expansions (this means by the way that the only consistent choice for the initial node is 1). You then superimpose those green lines and blue dotsby saying join dot r with dot t iff at least one of the following hold:
r=2t
t=2r
r=3t+1
t=3r+1
ok.
What youve observed is that at any level, it must be that there is a number that is sent outside that level to the next one, for instance you need to construct level k+1 and higher to indicate all th points where 2^k - 1 gets sent/can come from
let's address what you are claiming this implies.
In order to provide a proof of the Collatz conjecture in ZF, one must have all the Natural numbers. However it is in the assumption of the Collatz conjecture that the naturals exist and are a set in ZF. If we are not assuming the axiom of infinity, then the natural numbers do not form a set in the theory we are using, and hence Collatz is undefined in that theory. However, all the axiom of infinity states is that the natural numbers form a set, it does not imply the Collatz conjecture s true. The truth of the Collatz conjecture is not therefore equivalent to the axiom of infinity.
We must presume the axiom of infinity is in our set theory to define the Collatz conjecture, that is all.
the naturals exist, whether or not you chose to call them a set and do so independently of the set theory you use, there is nothing in what you've written to suggest that the assumption the naturals form a set is equivalent to Collatz being true or not.
I think the key here is your views on axiomatic set theory and the natural numbers, nothing to do with Collatz. The axiom of infinity just states that the naturals are an (inductive) set in ZF(C).
1. The binary tree is what i said it is - the infinite thing above. At the k'th level you number the nodes from 1 to 2^k using binary expansions (this means by the way that the only consistent choice for the initial node is 1). You then superimpose those green lines and blue dotsby saying join dot r with dot t iff at least one of the following hold:
r=2t
t=2r
r=3t+1
t=3r+1
ok.
What youve observed is that at any level, it must be that there is a number that is sent outside that level to the next one, for instance you need to construct level k+1 and higher to indicate all th points where 2^k - 1 gets sent/can come from
let's address what you are claiming this implies.
In order to provide a proof of the Collatz conjecture in ZF, one must have all the Natural numbers. However it is in the assumption of the Collatz conjecture that the naturals exist and are a set in ZF. If we are not assuming the axiom of infinity, then the natural numbers do not form a set in the theory we are using, and hence Collatz is undefined in that theory. However, all the axiom of infinity states is that the natural numbers form a set, it does not imply the Collatz conjecture s true. The truth of the Collatz conjecture is not therefore equivalent to the axiom of infinity.
We must presume the axiom of infinity is in our set theory to define the Collatz conjecture, that is all.
the naturals exist, whether or not you chose to call them a set and do so independently of the set theory you use, there is nothing in what you've written to suggest that the assumption the naturals form a set is equivalent to Collatz being true or not.
I think the key here is your views on axiomatic set theory and the natural numbers, nothing to do with Collatz. The axiom of infinity just states that the naturals are an (inductive) set in ZF(C).
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