Elliptic functions proof -- convergence series on lattice

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SUMMARY

The discussion centers on the convergence of the series ##\sum'_{w\in\Omega} |w|^{-s}##, specifically proving that it converges if and only if ##s > 2##, where ##\Omega## is a lattice defined by the basis ##{w_1,w_2}##. Participants explore the necessity of bounding the series from both above and below for the comparison test, as well as the application of the Weierstrass M-test. The cardinality of each subset ##\Omega_r## is established as ##8r##, which is crucial for understanding the series' behavior.

PREREQUISITES
  • Understanding of convergence tests in series, specifically the comparison test.
  • Familiarity with Weierstrass M-test and its application in complex analysis.
  • Knowledge of lattice structures in complex analysis, particularly the basis representation.
  • Basic concepts of sequences and series in mathematical analysis.
NEXT STEPS
  • Study the comparison test in detail, focusing on its application to series convergence.
  • Research the Weierstrass M-test and its implications for sequences of functions.
  • Explore the properties of lattices in complex analysis, including their cardinality and structure.
  • Investigate the implications of bounding series from above and below in convergence proofs.
USEFUL FOR

Mathematicians, students studying complex analysis, and anyone interested in the convergence of series and the properties of elliptic functions.

binbagsss
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Homework Statement


Hi

I am looking at the proof attached for the theorem attached that:

If ##s \in R##, then ##\sum'_{w\in\Omega} |w|^-s ## converges iff ##s > 2##
where ##\Omega \in C## is a lattice with basis ##{w_1,w_2}##.

For any integer ##r \geq 0 ## :

##\Omega_r := {mw_1+nw_2|m,n \in Z, max {|m|,|n|}=r} ##
##\Pi_r := {mw_1+nw_2|m,n \in Z, max {|m|,|n|}=r} ##

so that ##\Omega = {0} \Cup \Omega_1 \Cup \Omega_2 \Cup...##

Each ##\Omega_r## has cardinality ##8r##

QUESTIONS
- To prove via the comparison test, we only need to bound from above by a series that converges, so why have we bound from above and below - this is my main question really, why have we bound from above and below
- Does this proove via both the convergence test and the Weierstass-M test? Since each term in the sequence ##|w|^{-s}## is bound above by a real constant.
- The definition of the W-M test is ##u_n## a seqence of functions, if for each a ##n \in N## there exists ##M_n \in R## satisfying ##|u_n(z)|\leq M_n ## got all ##z \in E## where ##u_n : E \to C## and ##\sum M_n## converges. Here the '##u_n##' are ##|w|## are already taken the absolute value, does this change anything here or the W-M test or does it still apply in the same way?

Many thanks in advance.

Homework Equations


as above

The Attempt at a Solution


as above
 

Attachments

  • w s greater 2.png
    w s greater 2.png
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bump.many thanks.
 

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