Proving the Poisson Summation Formula: A Formal Approach

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The discussion centers on the proof of the Poisson summation formula, highlighting the need for clarity and precision in mathematical writing. A correction is noted regarding the notation of the Fourier transform, emphasizing that it should be denoted as f hat rather than f(n). Suggestions include making the change of variables explicit and ensuring consistency in notation throughout the proof. Additionally, the importance of objective language in formal proofs is stressed, advising against subjective phrases. Overall, the conversation focuses on enhancing the rigor and clarity of the proof presentation for an upcoming seminar.
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Homework Statement



Prove the Poisson summation formula.

Homework Equations





The Attempt at a Solution



Correction to image below: the very last line of the theorem (italicized) should say f hat is the Fourier transform, not f(n).

attachment.php?attachmentid=57796&stc=1&d=1365760686.jpg


Does this proof make sense and is it complete? I mean there are a million proofs online that are identical to mine but I am presenting this in a seminar tomorrow for my class so I wanted to make sure it was descriptive enough.
 

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I have a few small remarks.

First of all, I'd make the change of variables explicit (saying that you change to y = x + n).

Secondly, if you make that change, you should also change it in the exponent, so e^{2\pi i m x} becomes e^{2 \pi i m (y - n)}. You should then argue that the n can be dropped and replace the x with y in the next lines so that in the last line you get e^{2 \pi i m y}.

Finally, I wouldn't say "... the RHS is simple" in a formal proof. It's not an objective statement and doesn't add anything, just write "For the right hand side, notice that ...".

Also, what is F? And where are you using its periodicity?
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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