Let be a given positive integer. Prove that there is a -tuple of pair-wise coprime positive integers, each of which greater than such that
Note. by , we mean the greatest integer that doesn't exceed .
Solution
Notice that if are positive integers such that
while then would satisfy the condition of the problem. It thus suffices to find such numbers. We shall then prove the following lemma.
Lemma 1. Let and be rational numbers and and be distinct prime numbers. Then, , for all large enough positive integers .
Proof. Let . Let . It follows that . Thus, . Choose , it follows that , . Yielding . This proves our lemma.
We now construct . Let us denote by the first primes and be arbitrary rational numbers such that while . Then, choose a large enough and put , . It can be easily verified that these numbers would be satisfying the condition of the problem. ■
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