Difference between revisions of "2025 IMO Problems/Problem 3"

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Let <math>\mathbb{N}</math> denote the set of positive integers. A function <math>f: \mathbb{N} \rightarrow \mathbb{N}</math> is said to be bonza if <math>f(a)</math> divides <math>b^{a} - f(b)^{f(a)}</math> for all positive integers <math>a</math> and <math>b</math>. Determine the smallest real constant <math>c</math> such that <math>f(n) \leq cn</math> for all bonza functions <math>f</math> and all positive integers <math>n</math>.
 
Let <math>\mathbb{N}</math> denote the set of positive integers. A function <math>f: \mathbb{N} \rightarrow \mathbb{N}</math> is said to be bonza if <math>f(a)</math> divides <math>b^{a} - f(b)^{f(a)}</math> for all positive integers <math>a</math> and <math>b</math>. Determine the smallest real constant <math>c</math> such that <math>f(n) \leq cn</math> for all bonza functions <math>f</math> and all positive integers <math>n</math>.
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==Video solution==
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https://www.youtube.com/watch?v=vPqUTG4CW8w

Revision as of 21:57, 15 July 2025

Let $\mathbb{N}$ denote the set of positive integers. A function $f: \mathbb{N} \rightarrow \mathbb{N}$ is said to be bonza if $f(a)$ divides $b^{a} - f(b)^{f(a)}$ for all positive integers $a$ and $b$. Determine the smallest real constant $c$ such that $f(n) \leq cn$ for all bonza functions $f$ and all positive integers $n$.

Video solution

https://www.youtube.com/watch?v=vPqUTG4CW8w