by Guest » Thu Feb 20, 2020 11:53 am
If the construction were different it might hold, but one can't often neglect things in mathematics. I find that with these kinds of problems, breaking down the logic is most effective.
For f(n), {n/2 if n is even; 3n + 1 if n is odd}
As noted, the conjecture claims that all positive integer values converge to 1 in a finite number of steps.
It may be noted that all power-of-two conditions are fatal ("fatal" here meaning that the fate of convergence to one is set) if there is any point at which one appears, most decisively if in the perfect form 1*2ⁿ. It will be demonstrated in a bit that all single-digit whole numbers lead to convergence which plays a role in further conjecture.
The cycle at 9 is the longest of the single digit loss conditions, running through what could be called the "extended single-digit fatal cycle":
9-28-14-7-22-11-34-17-52-26-13-40-20-10-5-16-8-4-2-1 (Note that the "pure power of two" condition is forced to occur at the end, which occurs after a piece of the fatal condition 5*2ⁿ).
Because of the case of the cycle at 9, all single-digit conditions involving 1 (obvious), 2, 4, 5, 7, 8, and 9 (obvious) are fatal. Of the two single-digit potentialities remaining (3 and 6), one leads to the other (part of the fatal condition 3*2ⁿ) and they both lead to 10, which is part of the extended single-digit fatal cycle. Therefore, there is no single-digit integer condition that avoids convergence to 1.
Because of the power-of-2 extension condition, any number that may be perceived as a single-digit whole number multiplied by a power of 2 (i.e. {1-9}2ⁿ) is guaranteed to converge under the given constraints. Of these, the prime numbers give the most efficient tracking as they expose the greatest number of whole numbers that would converge. We may take this a step further and assert that any number divisible by two leads to convergence because the conditions guarantee even parity every time an odd number is encountered--the "+1" part of the odd condition is doing the code breaking work, the "3*" multiplier just makes the numbers more interesting but ultimately changes nothing about the gravity of descent once a power of two is reached. (Of great importance is the fact that this multiplier is an odd number; if it were even, all terms would become odd, and all values would grow without bound.) Because each set of numbers will hit a multiple of two at least once in every pair of iterations, achieving the "x + 1 = {1-9}*2ⁿ" condition is a matter of when, not if. All values will eventually converge to a single-digit number by landing on a multiple of a power of two. There must certainly be other known fatal spirals that can be mapped out as a result of the above conditions, at which point further calculations need not be run.
The demonstration of the long single-digit spiral, the proof that all single-digit values inevitably converge, and the exposure of the underlying modulo-2 condition in which all values are either even or becoming even makes it clear that for any and all positive whole values of n, the Collatz conjecture does in fact converge to 1--logically,at least. But, representing that purely mathematically may prove more troublesome.
-D. Sheppard
If the construction were different it might hold, but one can't often neglect things in mathematics. I find that with these kinds of problems, breaking down the logic is most effective.
For f(n), {n/2 if n is even; 3n + 1 if n is odd}
As noted, the conjecture claims that all positive integer values converge to 1 in a finite number of steps.
It may be noted that all power-of-two conditions are fatal ("fatal" here meaning that the fate of convergence to one is set) if there is any point at which one appears, most decisively if in the perfect form 1*2ⁿ. It will be demonstrated in a bit that all single-digit whole numbers lead to convergence which plays a role in further conjecture.
The cycle at 9 is the longest of the single digit loss conditions, running through what could be called the "extended single-digit fatal cycle":
9-28-14-7-22-11-34-17-52-26-13-40-20-10-5-16-8-4-2-1 (Note that the "pure power of two" condition is forced to occur at the end, which occurs after a piece of the fatal condition 5*2ⁿ).
Because of the case of the cycle at 9, all single-digit conditions involving 1 (obvious), 2, 4, 5, 7, 8, and 9 (obvious) are fatal. Of the two single-digit potentialities remaining (3 and 6), one leads to the other (part of the fatal condition 3*2ⁿ) and they both lead to 10, which is part of the extended single-digit fatal cycle. Therefore, there is no single-digit integer condition that avoids convergence to 1.
Because of the power-of-2 extension condition, any number that may be perceived as a single-digit whole number multiplied by a power of 2 (i.e. {1-9}2ⁿ) is guaranteed to converge under the given constraints. Of these, the prime numbers give the most efficient tracking as they expose the greatest number of whole numbers that would converge. We may take this a step further and assert that any number divisible by two leads to convergence because the conditions guarantee even parity every time an odd number is encountered--the "+1" part of the odd condition is doing the code breaking work, the "3*" multiplier just makes the numbers more interesting but ultimately changes nothing about the gravity of descent once a power of two is reached. (Of great importance is the fact that this multiplier is an odd number; if it were even, all terms would become odd, and all values would grow without bound.) Because each set of numbers will hit a multiple of two at least once in every pair of iterations, achieving the "x + 1 = {1-9}*2ⁿ" condition is a matter of when, not if. All values will eventually converge to a single-digit number by landing on a multiple of a power of two. There must certainly be other known fatal spirals that can be mapped out as a result of the above conditions, at which point further calculations need not be run.
The demonstration of the long single-digit spiral, the proof that all single-digit values inevitably converge, and the exposure of the underlying modulo-2 condition in which all values are either even or becoming even makes it clear that for any and all positive whole values of n, the Collatz conjecture does in fact converge to 1--logically,at least. But, representing that purely mathematically may prove more troublesome.
-D. Sheppard