Proving Euler's Phi Function: Any Help Appreciated!

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Discussion Overview

The discussion centers around proving a property of Euler's phi function, specifically that for positive integers m and k, the number of integers n such that 1≤n≤mk and (n,m)=1 is kφ(m). Participants seek clarification and proof of this assertion.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant states the property of the Euler's phi function and seeks a proof for it.
  • Another participant suggests using the division algorithm on n, proposing to express n as n=qm+r and to prove that (n,m)=(r,m).
  • Some participants express confusion regarding the concept of coprimes repeating in a "modular" fashion and seek clarification on this idea.
  • A participant elaborates that if c is coprime to m, then c+m and generally c+km are also coprime to m.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the explanation of the modular behavior of coprimes, as some express confusion while others attempt to clarify the concept.

Contextual Notes

There are unresolved assumptions regarding the understanding of modular arithmetic and the properties of coprime integers, which may affect the clarity of the discussion.

kingwinner
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"Let m and k be positive integers and φ(m) is the Euler's phi function. Then the number of integers n such that 1≤n≤mk and (n,m)=1 is kφ(m)."


I can't figure out why this is true. How can we prove it?

Can someone explain this, please?
Any help is appreciated!
 
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Coprimes repeat in a kind of "modular" fashion. You may try using the division algorithm on n, and expressing it as n=qm+r; then try to prove that (n,m)=(r,m).
 
hmm...sorry I don't understand. What do you mean by "Coprimes repeat in a kind of 'modular' fashion"?
 
kingwinner said:
hmm...sorry I don't understand. What do you mean by "Coprimes repeat in a kind of 'modular' fashion"?

If c is coprime to m, then c+m is coprime to m, and in general c+km is coprime to m.
 

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