Proof that algebraic numbers are countable

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The discussion centers on the proof that the set of all algebraic numbers is countable, as presented in Rudin's "Principles of Mathematical Analysis." The key argument is that for any positive integer N, there are finitely many polynomial equations of the form a_0*z^n + a_1*z^(n-1) + ... + a_n = 0, constrained by the condition n + |a_0| + |a_1| + ... + |a_n| = N. Participants debate whether the inclusion of n is necessary for establishing countability, with the consensus leaning towards its necessity to account for the infinite nature of n.

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In Rudin's Principles of Mathematical Analysis, exercise number two is to prove that the set of all algebraic numbers is countable. A complex number z is said to be algebraic if there are integers a_0, ..., a_n, not all zero such that

a_0*z^n + a_1*z^(n-1) + ... + a_(n-1)*z + a_n = 0

The hint given in the book is:
For every positive integer N there are only finitely many equations with

n + |a_0| + |a_1| + ... + |a_n| = N.

I understand the gist of how the proof works. The above equation partitions the algebraic numbers into a countable collection of finite sets, proving that the algebraic numbers are countable. But my question is this:

Couldn't we partition the algebraic numbers simply with the equation:

|a_0| + |a_1| + ... + |a_n| = N

Why add in the n when the each algebraic equation is fully characterized by the values a_0, a_1, ..., a_n? Or am I missing something?
 
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Is it obvious that only countably many equations satisfy

|a_0|+...+|a_n|=N

Note that n can get arbitrarily large here!
 
micromass said:
Is it obvious that only countably many equations satisfy

|a_0|+...+|a_n|=N

Note that n can get arbitrarily large here!

so are you agreeing or disagreeing with me that the n is unnecessary and can be dropped?
 

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