For every positive integer with prime factorization , define
That is, is the number of prime factors of greater than , counted with multiplicity.
Find all strictly increasing functions such that
[i]
For every positive integer with prime factorization , define
That is, is the number of prime factors of greater than , counted with multiplicity.
Find all strictly increasing functions such that
[i]
To solve this problem, we need to find all strictly increasing functions such that the condition given by:
holds for all integers and with .
### Step-by-step Solution:
1. Understand the Strictly Increasing Condition:
- Since is strictly increasing, for , we have .
2. **Analyzing Function**:
- The function computes the sum of the exponents of prime factors of that are greater than .
- For the inequality , must have "less complex" prime factors (in the sense of being smaller or having smaller exponent multiplicities) compared to .
3. Considering a Linear Function:
- A natural guess for a strictly increasing function from to is a linear function of the form , where and are integers.
- For linear functions, .
4. **Evaluate with Linear **:
- Substitute into the inequality: .
- Given that only considers primes greater than , and if does not introduce any prime factor greater than , then the inequality holds trivially.
5. Conclusion:
- Hence, any linear function with integer that ensures has no prime factors greater than satisfies the condition.
- The general form of the solution is:
where and are integers, and the prime factors of are all less than or equal to .
Therefore, the strictly increasing functions satisfying the condition are expressed by:
where is a positive integer whose prime factors do not exceed , and is any integer.