1. Introduction
We will use the following well-known fact: if, for the members of the Collatz sequence, zeros predominate in their binary representation, then these members will lead to a decrease in the subsequent members according to the Collatz rule. A striking example is when the initial number in the Collatz sequence is equal to . Let’s write the solution of the equation in the form and note that the smaller x, the more zeros in the corresponding binary representation for n. Developing this idea, we come to the following steps.
Analysis of the binary representation of simple cases of natural numbers.
Creation of a process for decomposing an arbitrary natural number into powers of two.
Analysis of the proximity of the process to binary decomposition at the completion of decomposition at each stage.
Calculation of the number of zeros in the binary decomposition of a natural number.
Estimation of the Collatz sequence members depending on the number of ones in the binary decomposition.
2. Results
This document reveals a comprehensive solution to the Collatz Conjecture, as first proposed in [1]. The Collatz Conjecture, a well-known unsolved problem in mathematics, questions whether iterative application of two basic arithmetic operations can invariably convert any positive integer into 1. It deals with integer sequences generated by the following rule: if a term is even, the subsequent term is half of it; if odd, the next term is the previous term tripled plus one. The conjecture posits that all such sequences culminate in 1, regardless of the initial positive integer. Named after mathematician Lothar Collatz, who introduced the concept in 1937, this conjecture is also known as the 3n + 1 problem, the Ulam conjecture, Kakutani’s problem, the Thwaites conjecture, Hasse’s algorithm, or the Syracuse problem. The sequence is often termed the hailstone sequence due to its fluctuating nature, resembling the movement of hailstones. Paul Erdős and Jeffrey Lagarias have commented on the complexity and mathematical depth of the Collatz Conjecture, highlighting its challenging nature. Consider an operation applied to any positive integer:
This operation is mathematically defined as:
A sequence is formed by continuously applying this operation, starting with any positive integer, where each step’s result becomes the next input. The Collatz Conjecture asserts that this sequence will always reach 1 Recent substantial advancements in addressing the Collatz problem have been documented in works [2]. Now let’s move on to our research, which we will conduct according to the announced plan. For this, we will start with the following
Theorem 1.
Let
Then for
and for
Proof. Consider
Then, we proceed to functional relations between
and
:
Evaluating for
, we get:
Continuing the computations for
, we obtain:
Thus, we obtain the final formulas. □
Proof. Let
Using Theorem 1, we construct the sequence
Suppose the binary decomposition process, according to formula (1), stops at the j-th step. It immediately follows that the remaining terms of the decomposition are zeros, and we immediately achieve the truth of the Theorem’s statement. Therefore, we consider the case when the generation of the decomposition according to formula (1) does not stop, and j reaches n. This means that all
.
Let’s conduct a more detailed analysis of the number of zeros and ones in our binary representation. Introduce the following notation:
l- the number of zeros in the binary representation.
m- the number of ones in the binary representation.
n- the binary decomposition bit size, then
n=l+m.
To solve the following equations
we introduce the notation
- the number of ones after the appearance of
and before the next appearance of zero in the binary decomposition and
Consider the set
by definition
Define:
if the set k satisfying the condition is not empty. Let’s perform a series of transformations to understand the next steps.
With the consideration of the definition of
, in case of existence
Introduce the notation
by definition
Rewrite equation (
6) using
and assuming that we have only one zero
It follows that after zero there cannot be more than three ones. Suppose that between two zeros there are two ones, using Theorem 1 and denoting
we get the system of equations
where
are defined below.
Using Theorem 1 again
Continuing the calculations, we obtain
from Theorem 1 and the last estimate implies
By considering three units between zeros, we obtain the following matrix:
The inverse of this matrix is given by:
We can also observe that the number of zeros is greater than the number of ones, which implies the statement of the theorem. □
Proof. Introduce operators defined as follows:
Consider all possible Collatz sequence behaviors that can be written as follows:
We need to calculate an estimate for each
-th term of the Collatz sequence based on the number of applied
operators within
n steps.
Let
have
m ones in its binary representation, then count the number of
Z operator applications by the following formula:
and the number of
P operator applications by the following formula:
Since each
Z application is followed by a
P operator, and the number of
P operator applications corresponds to the number of zeros in
, which is
. According to the Collatz rules, after
n steps we have:
According to the last formula, we see that the growth of each sequence member depends on the number of ones in its binary representation. Next, we show that a large number of ones on the
-th step leads to an increase in the number of zeros on the
-th step for the binary representation, according to the previous theorems, which implies a decrease in subsequent sequence members:
Repeating the reasoning of Theorem 2, consider the equation
From the last equation, to apply the results of theorem 2, we need
. To satisfy the last inequality, consider
,
Consider
we get
Choosing
l from even numbers less than 10, if the inequalities
Choosing
l from odd numbers less than 10, if the inequalities
Using
also satisfies the condition
According to theorem 2 we get
According to our application of the Collatz rules, we have an element
, and the order of its binary representation is
After
steps of applying the Collatz rules we have
By the definition of
we obtain
Using
, it follows that
. □
Theorem 4.
Let
then for the Collatz conjecture holds.
Proof. The proof follows from Theorems 1-3. □
Conclusion
Our assertion proves that after steps, the sequence with an initial binary length of n arrives at a number strictly less than the initial one, thus resolving the Collatz conjecture. Since applying this process n times will inevitably lead us to 1.
References
- O’Connor, J.J.; Robertson, E.F. (2006). "Lothar Collatz". St Andrews University School of Mathematics and Statistics, Scotland.
- Tao, Terence (2022). "Almost all orbits of the Collatz map attain almost bounded values". Forum of Mathematics, 10: e12. arXiv:1909.03562. ISSN 2050-5086. [CrossRef]
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